太空|TAIKONG ISSI-BJ Magazine No. 12 March 2019 SPACE SCIENCE SCHOOL ISSUE

ND THE 2

PACE SCIENCE S SCHOOL

STUDY EFFECTS FROM THE TO THE GROUND IMPRINT CONTENTS

太空 | TAIKONG Foreword 3 ISSI-BJ Magazine Introduction 4

School Overview 4

Address: No.1 Nanertiao, Sun/ 6 Zhongguancun, Haidian District, Study of some aspects of the solar energetic events of September 2017: active Beijing, region magnetic field, , , interplanetary shock Postcode: 100190 and solar energetic particles 6 Phone: +86-10-62582811 Website: www.issibj.ac.cn Impact and MIT Coupling 32

Multi-instrument observations of St. Patrick Storm 32 Editor Direct Observations of the Storm Event on 26 September 2011 42 Anna Yang cap patch evolution during a CME driven 50 / EISCAT Incoherent Scatter 61

Polar Ionospheric Response Observed by EISCAT on 7 September 2017 61

The variation of electron and ion during substorms and magnetic storms on 7 September 2017 70

Polar Ionospheric Response Observed by EISCAT and TEC on 8 September 2017 76

Three types Enhanced Electron Density phenomenon of Ionosphere in 9 September 2017: EISCAT Observations 85

Observation Results of Polar Ionosphere by ESICAT on Sep.10, 2017 89 Effects on Satellites and Ground-based infrastructures 98

Introduction to the topic 98

Flare Forecast & SID Analysis and Solar Proton Event (SPE) Forecast 103

Satellite Drag Analysis 106

2 太空|TAIKONG FOREWORD

When back in 2013 we discussed for the and published as this issue of TAIKONG first time the concept of the space science magazine. school, our vision was to organize for young space scientists and engineers a learning Space Weather is a timely and excellent by doing school, specially focused on research topic for students, since it analyzing data from space. However, for the combines in one-event, observed from the first edition, we decided to have a school on Sun to the Ground, different research fields “How to design a Space Science Mission” and topics. For completeness of the overall based on lectures. High-level experts and study of these topics, the 2018 school was well-recognized scientists, engineers, and also co-organized with the EISCAT Scientific space managers gave the lecturers. This Association. The school helped building was a highly successful school that left us links between the students, lecturers, and with unforgettable memories, i.e., a master tutors from different countries, where the example of friendships and professional students may have the potential to become networking coming from a joint effort leaders in the future, and collaborate with between different countries and expertise. the sole goal of benefiting the science. At the end of the school everyone, students, Everyone worked together to the benefit lecturers, and organizers took the lessons of the students, science, and brought this learned back home. school to a second successful millstone.

ISSI-BJ and APSCO understood very fast, We would like to thank all the sponsors that it is time for the second edition of the and supporters, and send warmly thanks school to involve the students more actively, to the very productive and efficient ISSI- learning by doing. So, this 2nd school was BJ staff: Lijuan En and Anna Yang, and first based on general lectures about Space APSCO staff: Bai Yu, who with dedication, Weather, but the second and main part was professionalism, and enthusiasm contributed devoted to letting the students work hard to organizing this school. We would like on Space Weather data guided by tutors. to extend our thanks and appreciation to The students were divided in four groups to APSCO Secretary-General Li Xinjun, as well analyze in parallel several extreme Space as EISCAT, Thomas Ulich (Director), and to Weather events. Each group produced a the China Remote Sensing Satellite Ground report, and all group reports were merged Station (RADI, CAS) for hosting this school.

Maurizio Falanga, Mohammad Ebrahimi Seyedabadi, Executive Director Director General

Department of Education and Training International Space Science Institute and Database Management, in Beijing (ISSI-BJ) Asia-Pacific Space Cooperation Organization (APSCO)

太空|TAIKONG 3 INTRODUCTION

School Overview

On October 10-19, 2018, reputation in teaching and The third day finished the 2nd ISSI-BJ and APSCO supervising participants. with the introduction to Space Science School with The opening lectures students group work, and EISCAT on Study Space revolved around the Sun a social dinner sponsored Weather Effects: From the and its connection to the by ISSI-BJ and APSCO to Sun to the Ground was Space Weather. The first help the students of each held at the Sanya Institute day of School concluded group break the ice. On of Remote Sensing (RADI) with a Welcome Reception Saturday afternoon, the in Sanya, Hainan Province, sponsored by the Embassy School Participants had China. Throughout the of Switzerland, the country an occasion to learn more school, 10 lecturers and where ISSI-BJ takes its about the Sanya Institute of 14 tutors from Asia and roots from. The School Remote Sensing during the beyond shared their Participants had an technical tour around the knowledge and experience occasion to get to know campus facilities. with 57 students from 10 each other while enjoying countries. the colorful buffet in the For the following week, open air. the students were divided The School started with into four working groups, a short introduction to On the following days, depending on their the school, given by experts gave an overview expertise and preferences: the organizers. The first of the Space Weather Sun/Heliosphere, Impact two and half a day of history, forecasting and and - School were dedicated to SW Science Program of Ionosphere-Thermosphere introductory lectures about ESA. After the talk on the Coupling, Ionosphere/ various elements of Space interplanetary coronal mass EISCAT Incoherent Scatter Weather given by the ejections, and the lecture Radars, and Effects on invited speakers, chosen on solar energy particles, Satellites and Ground- among experts and well- the following lectures based Infrastructures. The recognized scientists and brought the Space Weather groups were analyzing in engineers with an excellent topics closer to the Ground. parallel several extreme

4 太空|TAIKONG Space Weather events, constructive comments as welcome reception, such as the ones in after the lectures, but social dinner, technical September 2017. Each also with an intensive, tour, and excursion on group had its own theme week-long group work the free Sunday. It was a and agenda, using actual resulting in presentations wonderful and one of a observations as well as and reports. During the kind experience to see the computer models, and was students’ presentations space science research supported and guided by sessions, young scientists and engineering students tutors chosen among the had an occasion to present and lecturers from all over experts in the field. their research results, the world brought together, and receive invaluable exchanging their ideas The main task of the comments and advices also outside of the lecture working groups during from the experts in the hall, in the breathtaking the School was to prepare field. The final report surroundings of Sanya. the presentations of their including the reports During the closing results, serving as a basis written by all the working ceremony, with the lights to produce the final reports groups is published jointly dimmed, the students had which were merged and with APSCO and EISCAT a moment of emotion while published as this issue of in this TAIKONG ISSI-BJ watching the video with the the TAIKONG magazine. magazine. This TAIKONG most memorable moments All the groups finished the issue will be provided to of the School. After the big task with excellence, and all the School participants, success of the 2nd Space presented their outcome sponsors, and will be Science School, the third on the last day of School. widely distributed to the edition is planned in two media. years, in another member The School provided the country of APSCO. young space researchers Apart from the strictly and engineers with an scientific aspect, the All the materials related opportunity to gain the in- School also helped in to the School (including depth knowledge of the building links between handbook, links to the science of Space Weather, students and experts from presentations, video, etc.) observational methods and different countries. Young are available on the 2nd its relevance to applications scientists could develop SSS dedicated webpage: from the Sun to the ground. a professional network http://www.issibj.ac.cn/ The students actively during coffee breaks and Outreachs/Summer_ contributed to the School everyday meals, as well School/2nd_SSS_2018 not only with questions and as through such events

太空|TAIKONG 5 SUN/HELIOSPHERE

Study of some aspects of the solar energetic events of September 2017: active region magnetic field, solar flare, coronal mass ejection, interplanetary shock and solar energetic particles

Zimovets I.1,2,3, Wu S.4, Zhang R.2, Kocaman B.5, Xu Y.4, Xu M.6, Li D.4, Ding Z.4, Gu C.4, Honari Jafarpour M.7, Hu H.2, Hu Q.8, Li G.8, Liu R.6, Wang R.2, Zhou Y.9

1 International Space Science Institute – Beijing, China 2 National Space Science Center of CAS, Beijing, China 3 Space Research Institute of RAS, Moscow, 4 China University of Geosciences, Beijing, China 5 Tubitak Uzay, Ankara, Turkey 6 School of and Space Sciences, University of Science and Technology of China, China 7 Iranian Space Agency, Tehran, Iran 8 University of Alabama in Huntsville, USA 9 Nanjing University, China

Abstract

This is the report of the Sun/ of the extreme events of (electromagnetic radiation, Heliosphere group which September 2017, with the accelerated particles, worked at the 2nd APSCO major emphasis on the shock wave and coronal & ISSI-BJ Space Science September 10 event. As a mass ejection - CME) School with EISCAT. The result of the work, students to remote observers in purpose of this group were able to trace the interplanetary medium, in study was to acquaint development of the event, particular, near the Earth. students with modern starting from its initiation An important achievement methods of studying space in the active region on of the group activities weather sources based the Sun up to arrival of was the comparison on an example of analysis various disturbances

6 太空|TAIKONG of observational and it was found that the flare particles; 4) the performed modeling results. region was magnetically simulations with iPATH did connected to the Earth and not give good agreement Among the research could give direct access with the GOES observations results obtained, the of solar flare accelerated of this complicated long- following can be noted: energetic particles to the duration solar energetic 1) based on the analysis near-Earth space; 3) based particle (SEP) event, of the RHESSI, SDO/AIA, on the GCS modeling of although the arrival time GOES, and ground-based the STEREO-A/SECCHI of the interplanetary shock radio observations, it can EUVI, COR1 and COR2 is predicted well with an be concluded that the X8.2 jointly with SOHO C2 and accuracy of about one class flare on September C3 observations, the CME hour compared with the 10, in general, is consistent speed was estimated to observations of and with the standard model be around 2756±100 ACE. The simulation results of eruptive solar flares; 2) km/s in the heliocentric obtained for the September based on magnetic field distances of 7-18 solar 4 SEP event, for which the extrapolation with the PFSS radii. This speed was used was possibly model within the SolarSoft as the input parameter less disturbed by previous and approximation of for the iPATH modeling eruptions, are more interplanetary magnetic of acceleration and consistent with the GOES field by the Parker spiral, propagation of energetic observations.

I. Introduction

The purpose of this study 10. The main emphasis research is still actively was to introduce students was placed on the event of pursued (e.g., Chamberlin with the modern methods of September 10. These are et al., 2018; Chertok et studying the sources of the the last extreme events of al., 2018; Gary et al., space weather. Since the the space weather, they 2018; Gopalswamy et practice is the best teacher, were observed by a wide al., 2018; Liu et al., 2018, the training was based variety of modern ground- Omodei et al., 2018; Wang mainly on careful analysis based and space-based et al., 2018; Zhao et al., of a few recent famous instruments, they are 2018). Thus, students had space weather events of already well documented the opportunity to feel September 2017: 4, 6 and in the literature, while their themselves at the leading

太空|TAIKONG 7 edge of the space weather showed them the main and shock wave based research. resources for previewing on analysis of in situ and downloading data, plasma and magnetic field The group focused on four explained the basics of the measurements of Wind and main topics: (a) magnetic data processing methods. ACE; field in the source active After that, students region 12673; (b) flare were divided into small 5. iPATH modeling of dynamics and radiation; subgroups to work on the protons acceleration on (c) dynamics of coronal following individual, but the CME-driven shock and mass ejection (CME) related mini-projects: their propagation in IPM, and shock in the corona and comparison with in-situ and interplanetary 1. extrapolation of magnetic observations obtained by medium (IPM); (d) shock field on the Sun in the GOES. acceleration of ions potential approximation and transport in the using the PFSS model and As a result of the work on interplanetary medium in the NLFFF approximation these linked mini-projects, (IPM). Additionally, (SDO/HMI data were used); students were able to students were familiarized trace the development of with MPI/AMRVAC codes 2. study of the dynamics the event, starting from its for MHD modeling actively of the solar flare and its initiation in the active region used in solar physics. electromagnetic radiation on the Sun up to arrival The first three days were in the range from radio of various disturbances mainly spent on installing waves to hard X-rays (electromagnetic radiation, and debugging software using observations from accelerated particles, (SolarSoft, iPATH, GOES, RHESSI, SDO/AIA, shock wave and CME) to codes for extrapolation RSTN, and e-Callisto radio a remote observer in IPM, of magnetic field in the spectrometers; in particular near the Earth. NLFFF approximation, An important achievement etc.) necessary to perform 3. observation of the of the group activities the planned research. CME with SOHO/LASCO, was the comparison Students were also STEREO/SECCHI, and of observational and acquainted with the main modeling of its dynamics modeling data. Students modern space and ground- using the Graduated were able to practice the based instruments for the Cylindrical Shell (GCS) modern art of modeling study of solar flares, CMEs, model; severe space weather coronal and IP shocks, events, to experience its the solar wind and solar 4. determination of the capabilities and limitations. energetic particles. Tutors properties of the CME

8 太空|TAIKONG II. Extrapolation of magnetic field in the NLFFF approximation

So far, the routine have B· α = 0, indicating the Solar Dynamics measurement of solar that the scalar α is invariant Observatory (SDO) ∇ magnetic field is mainly along a given magnetic (Scherrer et al., 2012) for based on Zeeman effect field line. In general, α the time before the X9.3 which fails to measure varies in space, making class flare of September magnetic field in the corona the problem of finding 6, 2017. The data was due to low polarization, faint solution for magnetic downloaded from http:// intensity, and broad line field nonlinear. That is jsoc.stanford.edu/ajax/ width of coronal emission why this approximation is lookdata.html. This event lines. However, magnetic called as the non-linear rather than the September field is measured routinely force-free field (NLFFF) 10 event was selected at the photosphere. Thus, approximation. because the parent active if one need to understand region 12673 was on the the structure of magnetic To extrapolate magnetic solar disk. field in the corona, one way field in the NOAA active is to make extrapolation region 12673 we used the Field lines of the magnetic of photospheric field to NLFFF codes developed field extrapolated in the the corona using some by T. Wiegelmann NLFFF and potential approximations based (Wiegelmann, 2004; approximations are shown on physically reasonable Wiegelmann et al., 2012) in Figure 1. The NLFFF assumptions. One widely based on the optimization magnetic field lines are more exploited assumption is algorithm (Wheatland et al., complicated and sheared that the magnetic field (B) 2000). It should be mention than the potential one, as in the corona is force-free that the NLFFF package expected. Especially it field: j × B = 0, or j = αB, used gives opportunity can be seen around the i.e. electric current j flows to extrapolated potential magnetic polarity inversion along magnetic field. It is (current-free) magnetic line (PIL) shown by the based on an assumption field as well. As the input red arrow. This indicates that the plasma β (ratio boundary layer data we the presence of electric of plasma to magnetic used the photospheric currents in the core of the pressure) is much less vector magnetogram active region, the energy than unity in the low corona obtained with the of which could be released (e.g., Priest, 1982; Gary, Helioseismic and Magnetic during the subsequent 2001). Since ·B = 0, we Imager (HMI) onboard flare. A magnetic flux

∇

太空|TAIKONG 9 rope structure cannot loops can be seen there. the presence of a magnetic be seen along the PIL in However, more detailed flux rope in that region Figure 1, only an arch of analysis presented by before the flare. strongly sheared magnetic Wang et al. (2018) showed

Figure 1: Extrapolation of magnetic field in the active region 12673 before the powerful X9.3 solar flare on 6 September 2017 in the NLFFF (a,b) and potential (c,d) approximations. Side/ top views are shown on the left/right panels. Magnetic field lines are shown by yellow thin curves. Background is the photospheric line-of-sight magnetogram obtained with SDO/ HMI. Magnetic polarity inversion line is sown by the red arrow. Colorbar in the right shows the magnitude of the magnetic field in Gauss.

10 太空|TAIKONG III. Electromagnetic emission of the September 10 flare

To study the X8.2 solar process them using Imaging Assembly flare on September IDL and SolarSoft Ware onboard SDO (Lemen et 10 we investigated (SSW) to plot light curves al., 2012). The structure of electromagnetic emission in different wavelength each part consists of the of the Sun in the time interval ranges of electromagnetic three following aspects: between 15:00 and 17:00 spectrum from radio waves 1) brief introduction of UT using observational to hard X-rays. The second the data sources, 2) data data of different space- and part of this study was to processing, preparation ground-based instruments. combine the images of the of figures and its brief This study consists of flare sources observed by analysis, and 3) conclusion the two parts. The first the Ramaty High-Energy based on the analysis of part was to download Solar Spectroscopic the figures plotted. observational data of Imager – RHESSI (Lin et al., different instruments, 2002) and the Atmospheric

3.1. Light curves of the flare electromagnetic emission

3.1.1. Data sources

1. Geostationary Operational Environmental Satellite (GOES) 15, X-Ray Sensor – XRS (Machol & Viereck, 2016). Two data channels are available: 0.5-4 Å and 1-8 Å. The following standard data products are available in the “GOES” package in SSW: flux, flux time derivative, plasma temperature, emission measure, etc., with the time step of 2 s.

2. Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). Count rates in nine standard energy ranges (3-6, 6-12, 12-25, 25-50, 50-100, 100-300, 300-800, 800-7000, and 7000-20000 keV) are available with the time step of 4 s.

3. Radio Solar Telescope Network (RSTN). There are four RSTN radio observatories in the world: Learmonth (Western Australia), San Vito (Southern Italy), Sagamore Hill (Massachusetts, USA), Kaena Point (Hawaii, USA). Due to the time of the flare studied we used the data of the San Vito observatory. Light curves of radio emission at 8 single frequencies (245, 410, 610, 1415, 2695, 4995, 8800, and 15400 MHz) are available with the time step of 1 s.

太空|TAIKONG 11 3.1.2. Data processing

In this task, four panels data. The background The third panel of the were plotted (Figure 2). radiation was calculated by plot shows that the time The data shown in the first averaging values between derivative of the soft X-ray panel was obtained from two black solid lines on the light curves is similar to the San Vito observatory. left of the top panel. the light curves of the To see the more reasonable microwave emission. This and reliable radio wave The X-ray data of GOES is known as the Neupert data, first, the useless (left y-axis) and RHESSI effect (Neupert, 1968). column of information was (right y-axis) are shown deleted, and the useful in the second panel. It The fourth panel of data was saved to the TXT is exported to IDL as the Figure 2 obtained using files. The data then was SAV-files and restored in the GOES data shows that opened in the IDL and the IDL session. The result temperature of plasma in the background radiation shown were obtained after the flare plasma reached was subtracted from the some simple processing of almost 30 MK. the data in IDL.

3.1.3. Analysis and conclusion

Before the solar flare also seen at around 15:35 energy ranges of 6-12, occurred, the radio UT before the main flare 50-100, and 300-800 keV background-subtracted onset. respectively. There are fluxes detected by the San two missing parts in the Vito instruments basically In the second panel, the RHESSI data. There are floated up and down red and black light curves two basic reasons for these around zero-value in the correspond to the X-ray missing parts. First, when first panel. When the solar fluxes detected by GOES the spacecraft is in the flare started, the radio flux in the 0.5-4 Å and 1-8 Å eclipse it cannot measure curves increased rapidly ranges respectively. The X-ray coming from the Sun. and had different shapes blue, green and yellow Second, when it passes at different frequencies. curves obtained from the through the South Atlantic A radio precursor can be RHESSI data show X-ray Anomaly (SAA) region in the emission in three different

12 太空|TAIKONG Earth’s magnetosphere, it gyronsynchrotron emission trapping times. Since is switched off to protect the and bremsstrahlung microwave emission is detectors from the trapped radiation respectively mainly produced by more energetic particles. In produced by energetic energetic electrons than general, X-ray observations electrons accelerated bremsstrahlung radiation, of the flare are consistent in the flare region. the decay time (tail) of with the observations in Populations of accelerated microwaves emission is radio waves. electrons have energies in longer. It is consistent with a broad range. Electrons what we can in the first two Microwaves and hard with higher energies have panels of Figure 2. X-rays are mainly the different acceleration and

Figure 2: Time profiles of solar radio (top panel) and X-ray (second panel from the top) emission, its time derivative (third panel from the top) and plasma temperature (bottom) around the time of the September 10, 2017 X8.2 flare.

3.2. Sources of the flare electromagnetic emission

3.2.1. Data sources

We analyzed the following data in this work:

1. Ramaty High Energy Solar Spectroscopic Imager (RHESSI). Energy range: 6-12 and 50-100 keV.

2. Atmospheric Imaging Assembly (AIA) onboard SDO. Wavelength: 13.1 nm or 131 Å.

太空|TAIKONG 13 Figure 3: Observations of the X8.2 September 10, 2017 solar flare with SDO/AIA and RHESSI (above) and a cartoon (left) illustrating the “standard model” of eruptive flares (fromhttps:// www3.mpifr-bonn.mpg.de/staff/mmassi/c4-Model.pdf). The solar limb is shown by the thick white curve. The images were rotated.

3.2.2. Data processing

We considered three flare (X-ray emission) numbers of photons in the intervals: 15:53:20- respectively. To synthesize selected time intervals and 15:53:48, 16:03:55- X-ray images in two energy ranges; it should 16:04:28, 16:39:46- energy ranges, namely be above around 5000. 16:43:22 UT. They are 6-12 and 50-100 keV, X-rays in these ranges are indicated by the vertical we implemented Clean emitted respectively mainly dashed lines in Figure 2. algorithm to the RHESSI by the hot thermal plasma These three intervals data (Hurford et al., 2002). and non-thermal electrons represent the grow, peak The possibility to synthesize accelerated in the flare and decay of the solar images is judged by the region. The resulted images

14 太空|TAIKONG are shown in Figure 3 by level of 50% of the maxima AIA images and, the last red (6-12 keV) and green brightness of the sources. step, overplotted X-ray (50-100 keV) contours. The We created maps in SSW sources on the EUV images contours are plotted at a from the RHESSI and SDO/ obtained with SDO/AIA.

3.2.3. Analysis and conclusion

The observations of the and 50-100 keV emission poor convergence of the solar flare at different stages are in the coronal part of image synthesis algorithm are shown in Figure 3. these loops. Probably this due to the low photon flux A vertically extended is since footpoints of the in the flare decay phase. structure is faintly visible flare loops were behind the However, the cusp-shape in the EUV range in the west limb. In the second bright structure can be left panel of the left figure. and third left panels, the seen. It consists of two main plasmoid is not visible parts. The upper Y-shape any more, since it already Ultimately, we think that the part, most probably, is passed away of the SDO/ observations of this flare a bottom portion of an AIA’s field-of-view. At the are, in general, consistent erupting plasmoid (a flux same time, the flare loops with the “standard model” rope) with a quasi-vertical became larger and taller, of eruptive solar flares current sheet below it. and the X-ray sources (e.g., Shibata et al., 1996). The second, bright part in shifted upward. The large Its cartoon is shown in the the bottom, which has a apparent size of the 50-100 right panel of Figure 3 for cusp-like shape, is the flare keV source on the third left comparison. loops. The sources of 6-12 panel is probably due to the

IV. Magnetic connection of the flare site and the Earth

The September 10, 2017 was one of the hardest in the during this SEP event. X8.2 class flare and CME last decade (Gopalswamy Our aim is to examine were associated with et al., 2018). Energetic whether there was a direct a large solar energetic protons were detected in magnetic connection of particle (SEP) event that all GOES energy channels the flare site and the Earth,

太空|TAIKONG 15 Figure 4: The cartoon illustrating the idea to solve the considered problem of magnetic connection between the Earth and the flare region at the Sun. The Earth’s heliolongitude of around 29.3° is shown.

which could be considered interplanetary magnetic as a propagating path for field between the Earth and flare generated particles. the Sun. And then to check We use the Potential Field out whether these two kinds Source Surface (PFSS) of magnetic fields can be model to reconstruct the connected at the source coronal magnetic field surface, where magnetic starting from the active field is assumed to become region 12673 before the radial due to the solar wind flare, and then we use the action. The illustration of well-known Parker spiral the idea is presented in formula to approximate the Figure 4.

4.1. PFSS modeling

We use the PFSS package Figure 5 shows several have ends in the source within SSW to extrapolate reconstructed magnetic surface close to the ecliptic the photospheric magnetic field lines extended from plane, i.e. with small field to the solar corona. the parent active region heliolatitudes. Table 1 By assuming that electric 12673 of the flare to the represents the range of currents in the corona are source surface at 2.5Rs. Carrington heliolongitudes negligible, it implies that The opposite ends of the ( ) of the field lines’ ends the global solar magnetic “open” field lines starting in on the source surface φ field can be considered the active region end on the within the specific range approximately as potential source surface sphere in a of heliolatitudes ( ), the (Schrijver and DeRosa, certain quadrant bounded angular step is ±5°. It can θ 2003). Magnetic field is by some heliolatitudes and be seen that the range of assumed to be radial, due heliolongitudes. We need to heliolongitudes increases to the solar wind, at the find the angular boundaries just slightly when we source surface with the of this quadrant. We increase the range of radius of 2.5 solar radii (Rs) are mainly interested in heliolatitudes. from the Sun’s center. those field lines which

16 太空|TAIKONG Figure 5: Examples of the field lines reconstructed with the PFSS model randomly started from the active region 12673 before the September 10, 2017 X8.2 solar flare. View from the Earth is on the left and the view from the W90 direction is on the right. Closed/open filed lines are shown by white/pink. The background grey scale image is the photospheric line-of-sight magnetogram.

, deg ±5 ±10 ±15 ±20 ±25 ±30

θ min,deg 67.8 67.8 61.9 61.9 61.9 61.9 φ max,deg 163.0 163.0 163.0 163.0 163.0 163.0 φ

Table 1: The ranges of Carrington heliolongitudes ( ) depending on the ranges of heliolatitudes ( ) of the ends of the reconstructed magnetic field lines, starting in the active region, on the φ source. θ

4.2. Interplanetary magnetic field

We assume that the ≈ ss-w/v(r-rss), source surface from the interplanetary magnetic (1) Sun’s center, v is the solar φ φ field before the event can wind speed, ω is the solar where r is the radial distance be approximated by the angular rotation rate, ss is Parker Archimedian spiral from the Sun’s center, rss an initial heliolongitude of φ (Parker, 1958): is the radial distance of the a field line on the source

太空|TAIKONG 17 surface. In our case r heliolongitude was ≈29.3° Thus, we can conclude that is equal to 1 A.U. and during the time of interest. the flare region could have φ rss=2.5Rs. Using Wind Using equation (1), we find direct magnetic connection observational data, we that ss is in the range from with the Earth, and flare can get the range of the to 71.7° to 82.5°. It is within accelerated particles could φ solar wind speeds around the found range [ min, max] contribute to the fluxes the Earth from around 430 of the reconstructed field of energetic particles φ φ to 540 km/s in the time lines’ ends on the source measured near the Earth. interval related to our study. sphere (Table 1). The Earth’s Carrington

V. Observations and modeling of the CME

CMEs are large ejection standard CME has three Earth. Fast CMEs can drive of plasma and magnetic parts: a bright front, a fast forward shocks ahead field from the Sun’s corona. dark cavity, and a bright of them which are thought Based on many years core (Figure 6). CMEs to be responsible for long- white-light observations, travel outward from the duration SEP events. CMEs it was found find that a Sun at speeds ranging expand in size as they from slower propagate away from the than 250 Sun, therefore they can km/s to near reach a large-scale size. 3000 km/s. The fastest The fast CME of the Earth- September 10 event directed occurred from NOAA active CMEs can region 12673 located reach our around S09W92. It was planet in 15- observed by the SECHHI 18 hours. EUVI, COR1 and COR2 on Slower board the STEREO-A as CMEs can well as by the LASCO C2 take several and C3 onboard the SOHO. The CME first appeared Figure 6: An example of SOHO/LASCO days to observation of a typical CME with three major achieve the at about 16:00 UT. To get parts (reproduced from the NASA website).

18 太空|TAIKONG face-on edge-on position

Figure 7: Illustration of the GCS model. (reproduced from Thernisien et al., 2009) the parameters of this face-on and an edge-on we need to change these CME, we implement the representation of the model parameters to construct a graduated cylindrical shell respectively. The dash- good morphology, which (GCS) model to the CME dotted line represents the can cover the CME white white light images obtained axis of the model and the light image from both from two viewpoints almost solid line the outline of the STEREO-A and SOHO. simultaneously (Thernisien shell. hfont represents the et al., 2009). height of the CME. α is the Figure 8 shows the fitting half-angle between the results at one moment. The GCS model is meant to legs; a is the radius of the The top two panels present reproduce the large-scale cross section and r is the the running difference structure of flux-rope-like distance from the center of white light images from CMEs. It consists of a the Sun to the nose point STEREO-A and SOHO. tubular section forming the at the edge of the shell. In the bottom two panels, main body of the structure Aspect ratio κ is the ratio the GCS output (the green attached to two cones that between a and r. Panel wireframe) is overlaid on correspond to the “legs” (c) shows the positioning the images. The GCS of the CME flux rope. The parameters: and are model can well reconstruct resulting shape looks like the longitude and latitude, the topology of this CME. φ θ a croissant. Panels (a) and respectively, and γ is the For this CME event, we did (b) of Figure 7 show the tilt angle. In this study, the GCS fitting at 4 different

太空|TAIKONG 19 times. Table 2 shows the fitting results. Columns from left to right shows the fitting time, longitude and latitude of the CME propagation direction, tilt angle, aspect ratio, half angle, and CME height. Only the height of the CME changes with time.

Since we can get the CME heights at different times, we can then fit the CME speed. The CME height-time plot is shown in Figure 9. According to the linear fitting result, this CME has a speed of 2756 Figure 8: An example of the GCS model implementation to STEREO-A (left) and SOHO (right) observations of the CME km/s with the error of 100 during the September 10, 2017 event. km/s in the heliospheric distances from 7.5Rs to 18.2Rs. The estimated CME speed will further be used in the iPATH model to simulate acceleration and propagation of charged particles in the inner heliosphere.

Figure 9: Height-time plot of the September 10, 2017 CME made using the GCS model.

20 太空|TAIKONG Instruments Time Lon Lat Tilt angle Ratio Half Height (UT) Angle (Rs)

C2 16:12 W110 S9 20 0.73 55 6.5 Cor2 16:09

C3 16:30 W110 S9 20 20 55 10.7 Cor2 16:24

C3 16:42 W110 S9 20 20 55 14.0 Cor2 16:39

C3 16:54 W110 S9 20 20 55 17.2 Cor2 16:54

Table 2: GCS modeled parameters for the 2017 September 10 CME

VI. Identification of the interplanetary shock

Interplanetary shocks the ambient solar wind. to investigate parameters (IPSs), which are driven They are featured by the of the solar wind near by interplanetary CMEs abrupt increases in the the Earth to identify the (ICMEs) and can travel to magnetic field strength IPS related to the 2017 the Earth and beyond, have and solar wind plasma September 10 CME. been observed in situ by a parameters, including Then we can compare number of spacecraft (e.g., plasma density, velocity observational results with Jones & Ellison, 1991). The and temperature. IPSs the results obtained from IPSs are formed when the are believed to accelerate the iPATH modeling. disturbance propagates ions and electrons to very remarkably faster than high energy. Our aim is

6.1. Data source

We used the data from the The ACE spacecraft the Sun to establish ACE and WIND spacecraft was launched in 1997 to the commonality and near the Sun-Earth investigate, in particular, interaction between the Lagrangian point (L1). the matter ejected from Sun, Earth, and the Milky

太空|TAIKONG 21 Way galaxy. In addition, The WIND spacecraft instrument MFI and SWE ACE also provides real- launched in 1994 contains onboard WIND (https:// time space weather data eight instruments for www.nasa.gov/connect/ and advanced warning of investigating the solar ebooks/beyond_earth_ geomagnetic storms. We wind interacting with the detail.html). use the data measured Earth’s magnetosphere by the instruments MAG and ionosphere. Its All the data analyzed here and SWEPA onboard ACE has changed in ten years were downloaded from the (Stone et al., 1998). after the launch, and by CDAWeb. Table 3 shows 2004 it arrived at L1 point. the information about the We use the data from the data format in detail.

ACE WIND

Magnetic field [MAG] [MFI]

|B|, B_GSE (16s level 2 data) |B|, B_GSE (92s) Plasma parameters [SWEPAM] [SWE]

Np, Vp, Tp (64s level 2 data) Np, V_GSE

Thermal_speed (92s) Duration 2017/09/12-2017/09/14 ( 3 days )

Table 3: ACE and WIND spacecraft data format

6.2. Results of the analysis

We combine all in temperature is calculated the shock arrived at the situ measurements in from the thermal speed. ACE. We think that the Figure 10. The velocity Through Figure 10 we can lag is probably due to the of solar wind protons get the shock’s arrival time small difference in from WIND is calculated at WIND that is about 19:20 of the two spacecraft. from three components of UT on 2017 September The difference between measured velocity and the 12, and 11 minutes later the observed and iPATH

22 太空|TAIKONG modeled (see below) speed, we use the data 540 km/s and it is used in arrival times of the shock from the WIND because the iPATH model in section at the Earth is just one there is a lack in the ACE VII below. hour, which is quite small. data (see Figure 10 left). To estimate the solar wind The speed range is 430-

Figure 10: Magnetic field and plasma parameters at the Sun-Earth L1 point on 2017/09/12-14 measured by ACE (left) and WIND (right). The arrival time of the ICME driven shock associated with the 2017 September 10 major event is shown by the red vertical dashed line.

太空|TAIKONG 23 VII. iPATH modeling of the SEP events

Using recently extended (assumed spherically 3) Transport module: 2D improved Particle symmetric) and a this model is based on the Acceleration and Transport propagating CME-driven focused transport equation in the Heliosphere (iPATH) shock; modified with a cross field model (Hu et al., 2017), we diffusion term, which is model September 10, 2017 2) Acceleration solved using a backward gradual SEP event. module: 2D onion shell stochastic differential module where injected equation method. The iPATH model consists particles are accelerated Specifically, we use a of three main parts: by the diffusive shock Monte-Carlo approach to acceleration (DSA) track the propagation of 1) MHD module: mechanism and diffuse quasi-particles. a hydrodynamic ZEUS between shells within the code that simulates the shock complex; background solar wind

7.1. SImulation results and discussion

For the background solar points in the longitudinal ( ) background by a factor of wind used in this event, the direction. We perturbed the 6 and the CME speed was φ 8-hour averaged proton inner boundary to launch set to 2500 km/s, which is number density, solar wind the CME with a center consistent with the CME speed and total magnetic longitude of c=100° and speed estimated from field at 1 A.U. before the an angular half width of 65°, the GCS modeling of the φ event start was calculated and to generate the CME- observations (see section to obtain input parameters: driven shock. We allowed V). N≈0.8 cm-3, v≈495 km/s the perturbation of the and B≈3.9 nT respectively. number density, solar wind Figure 11 shows the model The simulation was run on temperature, and speed CME of this event. In the a 2D domain with 1,500 at the boundary to have a iPATH model, we do not grid points in the radial (R) longitudinal dependence. model the CME itself. direction (from 0.05 A.U. We increased the Instead, we introduce to 2.0 A.U.) and 360 grid number density from the a disturbance to drive

24 太空|TAIKONG shock speed vshk along the shock front respectively. Note the clear longitudinal

dependence of Rshk due to the nose propagating faster and the flanks slower. Figure 12 (bottom right) shows the shock obliquity angle. In general, our simulation shows that the CME-driven shock at later times remains quasi- parallel at the eastern flank and becomes increasingly quasi-perpendicular at Figure 11: A snapshot of the configuration for the fast CME- the western flank as time driven shock of the September 10, 2017 SEP event obtained increases. This assumes with iPATH model. The simulation domain is from 0.05 to 2 A.U. a nominal Parker spiral The color scheme is the normalized density NR2. The bold black field in the interplanetary circle at 1 A.U. indicates the Earth orbit. Earth reference point at space. When a preceding longitudes of 0° are shown. The dashed line is the Parker spiral CME exists and perturbs field line connecting the reference point to the shock front. the interplanetary medium, this longitudinal the CME shock. The lines can be found inside dependence of the shock color scheme is for the the sheath region. obliquity does not hold normalized density (NR2). anymore. Incidentally, the The high-density blob Figure 12 (top left) shows presence of a preceding in the figure represents the shock compression CME may be important the density disturbance ratio (s). We impose for large SEP and Ground

in the iPATH model. It an upper limit smax=3.9. Level Enhancement (GLE) compresses the solar wind Throughout the simulation, events. in the upstream, forming the compression ratio is a ahead and peaked near the nose Comparison of the model leaving a density cavity of the CME. Figure 12 results with the observations behind the CME structure. (top right and bottom at the Earth reference point Twisted magnetic field left) plots the heliocentric for the September 10 event

shock location Rshk and the is shown in Figure 13. The

太空|TAIKONG 25 Figure 12: Parameters along the CME-driven shock front at different times calculated with the iPATH model. (top left) The shock compression ratio as a function of longitude . (top right) Heliocentric distance of the shock front as a function of longitude. (bottom left) Shock speed φ as a function of longitude. (bottom right) Shock obliquity angle θBN as a function of longitude. Different colors represent different times (shown in the figure in hours) after shock initiation. A strong longitudinal dependence can be seen for these parameters. left panel shows the proton smaller than the observed from the CME nose. This flux measured by GOES. ones. However, the Earth means that the Earth is In the right panel we is well connected with the barely connected to the plotted the iPATH results. CME ejecta, so one can weaker eastern flank, so These results are not in see an instantaneous and the simulated proton fluxes good agreement with the sharp enhancement at decrease much faster. observations. In particular, the CME initiation. When the simulated peak fluxes the CME propagated out, Some important factors and decay times are the Earth is about 100° were not taken into

26 太空|TAIKONG Figure 13: Proton fluxes obtained from the iPATH simulations (left) and GOES observations (right) for the September 10, 2017 event. The starting and ending simulation times shown on the left panel are marked with the 2 vertical solid lines on the right.

Figure 14: Proton fluxes obtained from the iPATH simulations (left) and GOES observations (right) for the September 4, 2017 event. The starting and ending simulation times shown on the left panel are marked with the 2 vertical solid lines on the right. consideration in this particles in event studied, of the CME (Figure 13). simulation. 1) Since there however, we suggested It is speculated that the were several eruptions a stable solar wind in our CME may have a certain before September 10, it simulation. 2) The proton turn toward the Earth side is possible that increased flux measured by GOES- during the propagation that seed population could 13 did not decrease within makes the magnetic field increase the flux of energetic 24 hours after the start connection between the

太空|TAIKONG 27 Earth and the strong region for the difference between It is worth mentioning that of the shock to be better the simulation and the solar wind was quite than in the simulation. 3) observations. stable in this event, since Contribution of energetic there were no preceding particles from the flare As a secondary task, strong CMEs and flares region at the Sun is also we also simulated the before this CME eruption. possible. Our simulation September 4, 2017 event. This makes the simulation does not consider the The simulation results are in more accurate than for the factors mentioned above, better agreement with the September 10 SEP event. which may be the reasons observations (Figure 14).

7.2. iPATH modeling conclusion

Using iPATH model we an intrinsic 2D model, the events such as the made simulations of the iPATH model provides a September 10 event, the intensity time profiles of working basis to interpret iPATH model is a significant energetic protons detected observations. Although tool for understanding SEP by GOES near the Earth the iPATH model may not events. for the September 10 and simulates very accurately 4, 2017 SEP events. As some very complicated

VIII. General conclusion

The aim of our group was Based on the analysis of PFSS package in SSW to assay some widely the RHESSI, SDO/AIA, and approximation of used approaches and GOES, and some ground- interplanetary magnetic methods for analysis of based radio observations field by the simple Parker the solar extreme events we concluded that the X8.2 spiral it was found that of September 2017, with class flare on September the flare region could be the major emphasis on 10, in general, is consistent magnetically connected the September 10 event. with the “standard model” with Earth that may give In the course of this one of eruptive solar flares. direct access of energetic week work we obtained 2) Based on magnetic particles accelerated in the following results. 1) field extrapolation with the the flare region to the near-

28 太空|TAIKONG Earth space environment. from the Sun. 4) The a) neglect of the increased 3) Based on the GCS performed simulations seed particle population modeling of the STEREO-A/ with iPATH did not give from the previous events; SECCHI EUVI, COR1 and good agreement with the b) lack of 2D symmetry of COR2 jointly with SOHO C2 GOES observations of interplanetary magnetic and C3 observations, we the complicated gradual field in the ecliptic plane; estimated the CME speed SEP event of September c) solar flare contribution to be around 2756±100 10, although the arrival to the fluxes of energetic km/s in the heliospheric time of the interplanetary particles. The simulation distances of around 7-18 shock is predicted with results for the weaker SEP solar radii. This speed an accuracy of about one event of September 4, in was used as the input hour compared with the which the aforementioned parameter for the iPATH observations of WIND and factors could probably play simulation of acceleration ACE. Possible explanations less important role, are in and propagation processes for the divergence of better agreement with the of energetic particles in the the iPATH results and GOES observations. inner heliosphere within observations of this solar 0.05-2.00 A.U. distances energetic particle event are:

Acknowledgments

We thank the teams of of SSW used in this study. to the organizers of the 2nd ACE, RHESSI, GOES, We are also grateful to APSCO & ISSI-BJ Space SDO, SOHO, STEREO, Dr. T. Wiegelmann (MPS, Science School with WIND, RSTN, e-CALLISTO ) for permission to EISCAT for the excellent for the freely available use his NLFFF codes. We opportunities provided. data and the developers express special gratitude

References

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太空|TAIKONG 29 Chertok I.M., Belov A.V., Abunin A.A. Solar Eruptions, Forbush Decreases, and Geomagnetic Disturbances From Outstanding Active Region 12673 // Space Weather, 2018, https://doi.org/10.1029/2018SW001899

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太空|TAIKONG 31 IMPACT AND MAGNETOSPHERE-IONOSPHERE- THERMOSPHERE COUPLING

Multi-instrument observations of St. Patrick Storm

Amarjargal Bat-erdene1, Linxin Zhao2 and Xiuhong Han3 1 Institute Astronomy and Geophysic, Mongolian Academy of Science 2 Shandong Unversity 3 Hebei GEO Unversity

Abstract

In this work we studied multi- flow and polar cap patch the particle precipitation instrument observation during the St. Patrick in the cusp ionosphere of the St.Patrick’s Day Storm on 17 March 2015 observed by the EISCAT geomagnetic storm of made by the Super Dual (European incoherent 2015. We show the high- Auroral Network Scatter) UHF (ultrahigh resolution observations of (SuperDARN), the Global frequency) radar in Tromsø, the temporal and spatial Positioning System (GPS), (69.58°N, 19.23°E; evolution of the convection respectively. We also show 66.73° N MLAT).

I. The 2015 St. Patrick’s Day Storm

First we use the EART’s bow shock nose indicated by the increased interplanetary magnetic (King & Papitashvili, 2005). SYM-H. Geomagnetic field (IMF) in geocentric The pressure of Solar storm and global response coordinates from the wind compresses on the in geomagnetic indices. 1 min resolution OMNI dayside of Earth. Solar The Geomagnetic storm data set. The Omni IMF wind dynamic pressure is driven by CME from the data are shifted from the triggered a sudden storm Sun. (Kamide & Kusano, observation points to the commencement (SSC) as 2015; Kataoka et al., 2015).

32 太空|TAIKONG Figure 1: Geomagnetic activity and solar wind parameters during 16-18 March 2015, OMNI IMF Bz, By, solar wind velocity Vsw [km/s], dynamic pressure Pdyn [nPa], and geomagnetic activity SYM-H [nT] of the Patrick’s Storm.

Figure 2: The Geomagnetic observatory. in Lanzhou (LZH) Component X[nTl], Y[nTl], Z[nT] and Geomagnetic activity for the March 2015

太空|TAIKONG 33 Figure 1. shows the red There are three phases of to the main phase of line at 06:00UT on 17 the Geomagnetic Storm: geomagnetic storm (when March 2015, SYM-H line growth phase, main phase the decrease of the SYM-H increased. This is SSC. and recovery phase. index takes place ) or during the storm sudden After SSC, the SYM-H index Secondly, we studied commencement (which at 07:00UT decreased to Magnetometer data for appears as a Dst increase at reach -200nT at 23:00UT INTERMAGNET. the beginning of the storm) on this day and started since during these phases this time increasing until During the event on 17 some magnetospheric 12:00UT on 18 March March 2015 at observatory currents are enhanced. 2015. During this time (from LZH, the Waveform data SSC and decrease of the 07:00UT 17 March to18:00 from Lanzhou (LHZ), SSc caused by enhanced UT 18 March) there was the (Geomagnetic component- current Geomagnetic storm on the X,Y,Z) and Geomagnetic flow eastward following Patrick’s day. activity index SYM/H are decrease caused by similar. Most problems in increased current ring. utilities have been related

II. Observations by using superDARN radar and GPS TEC

2.1. The response of ionosphere to the magnetic storm.

In Figure 3 we can see that westward convection region becomes red, which when the storm occurred, flow was observed by the means the convection the convection cell superDARN radar. Look at flow is very strong. These expanded equatorward the black circle in the 4th observations show us the in a very short time. picture of Figure 3, the data response of the ionosphere Meantime, enhanced of the superDARN in this to the magnetic storm.

34 太空|TAIKONG Figure 3: Convection flow observed by the superDARN radar on Match 17, 2015.

2.2. An evolution of a polar cap patch

In Figure 4 we can see observed in the duskside. another polar cap patch that during the storm, Several minutes later, TOI accompanied with strong an evolution of a polar detached and formed the anti-sunward convection cap patch was found by polar cap patch. Then the flow was observed in the using the GPS TEC map. patch moved along the polar cap center. We will We focus on the detail of convection pattern. check more instrument the evolution, the top two data in our further work. figures show the TEC map of In Figure 5 we can see how the patch was formed: that when this patch is first, around 17:30, TOI was moving to the nightside,

太空|TAIKONG 35 Figure 4: GPS TEC map on March 17, 2015.

36 太空|TAIKONG Figure 5: GPS TEC and Convection flow map at 18:50-18:55 on March 17, 2015.

III. Observations from EISCAT radar

3.1. Introduction

The European Incoherent and elevation angle of 77° be processed using the Scatter (EISCAT) UHF (i.e., in the field-aligned GUISDAP analysis toolbox (ultrahigh frequency) direction in the F region). (http://www.eiscat.com/ radar is in Tromsø, Norway The figures in this part were groups/Documentation/ (69.58°N, 19.23°E; 66.73° directly downloaded from UserGuides/GUISDAP/; N MLAT). The UHF radar the Madrigal homepage Huuskonen & Lehtinen, beam was fixed at an (https://www.eiscat.se/ 1996). azimuthal angle of 185° madrigal/). The data can

3.2. Particle Precipitation

Figure 6 shows a multi- temperature, Te, ion by the EISCAT UHF radar panel plot of the electron temperature, Ti, and ion drift from 20:00 to 24:00 UT. density, Ne, electron velocity, Vi as measured During this period of time,

太空|TAIKONG 37 Figure 6: Particle precipitation observed by the EISCAT UHF radar at Tromsø, Norway from 20:00 to 24:00 UT.

38 太空|TAIKONG Figure 7: Ionospheric parameters observed by the EISCAT UHF radar at Tromsø, Norway from 10:50 to 13:50 UT.

太空|TAIKONG 39 we can see in Figure 6 angles can precipitate to the increase of the ion that the interplanetary low altitudes [McCrea et temperature in the third magnetic field (IMF) Bz was al., 2000]. The energetic panel of Figure 6. The continuously southward particles gradually transfer electron temperature in the with a magnitude of about their energy to the upper second panel of Figure 6 -20 nT. The strongly atmosphere via various do not show accompanied southward IMF Bz favors collisions and meanwhile increase because the dayside magnetopause caused excitation and GUISDAP toolbox failed reconnection, generating ionization of atmospheric to analyze the electron open field lines along gases, resulting in . data. The increase of which plasma is free to flow Thus, in the process of the temperature caused across the magnetopause particle precipitation, the increase of the scale boundary. Plasma crossing we can see in the first height, which resulted in the dayside magnetopause panel of Figure 6 that the the upward flow of the along newly opened electron density increases ions in the fourth panel of field lines is accelerated at around 20:40, 21:20, Figure 6. Earthward, so that the 22:00, 22:28 and 23:30 particles with low pitch UT, accompanying with

3.3. TEC blob

Figure 7 shows the same to 13:36 UT the electron due to strong Joule heating, ionospheric parameters as temperature was enhanced but the enhancement in the that in Figure 6 from 12:50 due to active electron electron density (300-500 to 13:50 UT. From 13:04 to precipitation, and the ion km) was actually due to the 13:14 UT and from 13:26 temperature was enhanced TEC blob [Jin et al., 2018].

Acknowledgement

We acknowledge data from Kyoto (WDC), and data for school for providing us an Omni https://cdaweb.sci. INTERMAGNET. Thanks to opportunity to learn from gsfc.nasa.gov, World Data The second APSCO and and work with the worldwide Center for Geomagnetism, ISSI-BJ space science famous scientists. Thanks

40 太空|TAIKONG to our tutors, Yaqi Jin, Zhang for their patience. Thanks to the ISSI-BJ staff Jianjun Liu and Qinghe for organizing this school.

Reference

Huuskonen, A., & Lehtinen, M. (1996). General incoherent scatter analysis and GUISDAP error estimates valid for high signal strengths. Journal of Atmospheric and Terrestrial Physics, 58(1–4), 435–452. https://doi.org/10.1016/0021-9169(95)00047-X

Jin, Y., & Oksavik, K. (2018). GPS scintillations and losses of signal lock at high latitudes during the 2015 St. Patrick’s Day storm. Journal of Geophysical Research: Space Physics, 123. https://doi.org/10.1029/2018JA025933.

Kamedie, Y., and K.Kusano( 2015), No major Solar Flares but the Lagest Geomagnetic Storm in the Present Solar Cycle, Space Weather, 13,365-3678 doi:10.1002./2015/ SW001213

Mccrea I W , Lockwood M , Moen J , et al. (2000). ESR and EISCAT observations of the response of the cusp and cleft to IMF orientation changes[J]. Annales Geophysicae, 18(9):1009-1026. DOI:10.1007/s00585-000-1009-7

太空|TAIKONG 41 Direct Observations of the Storm Event on 26 September 2011

Tsung-Yu Wu, National Central University, Taiwan Pugazhenthi Sivasankar, Delft University of Technology Aerospace Engineering, Netherlands Yong Ren, National Space Science Center, CAS, China Ismail Demirhan, Tubitak Space Technologies Research Institute, Turkey

Tutors: Yaqi Jin, University of Oslo, Norway; Jianjun Liu, Polar Research Institute of China, China Qinghe Zhang, Shandong University, China

Abstract

The global positioning electron/ion temperature storm extending to higher system total electron (Te and Ti), and plasma altitudes in polar region content (GPS/TEC), Super velocity coverage among (~200 km). Data analysis Dual Auroral Radar Network polar and mid-latitude of SuperDARN and GPS/ (SuperDARN), Poker Flat region. Both the plasma TEC show polar cap patch Incoherent Scatter Radar density and temperature convection during the of Madrigal, and Gravity increase during the storm period from 17:50 to 21:25 Recovery and Climate period at night side due UT, as well as the night side Experiment (GRACE) to the night side magnetic magnetic reconnection satellite have been used to reconnection. Moreover, process. During the same analyze the geomagnetic the ratio of Te/Ti shows the period, the orbit of the storm effects in the polar Te to be 2-2.5 times greater GRACE satellite showed region on 26 September than Ti during the storm variation which can be 2011. Poker Flat Incoherent period. The analysis of attributed to the change in Scatter Radar, located at the Poker flat radar beam neutral density due to the (65oN, 147oW), provides on 26 September, 2011 storm. the electron density, also shows the effect of

42 太空|TAIKONG I. Introduction

Space weather is primarily the ionosphere. The patches during the sub- governed by coronal mass electrons in the ionosphere storm is discussed in the ejections (CMEs), solar accelerate in response to sections below. flares and solar energetic the incident waves from particle events (SEPs). On the radar and reradiate the The interaction between 26 September 2011, a CME signals. These signals are the Interplanetary arrived at the Earth and this received by the receiver Magnetic Field (IMF) caused a geomagnetic and are processed to and the geomagnetic storm. Due to the energy obtain electron and ion field influences the polar and momentum deposition temperatures, velocities ionosphere, which in turn of this storm into the and number densities. affects the thermosphere Earth’s upper atmosphere, density. The response of the the thermodynamics, SuperDARN is a network thermosphere is quantified electrodynamics, and of high latitude radars that by the parameter, Total composition in the use coherent scattering precipitation power, UA. thermosphere and to measure the velocity of Earlier efforts to measure ionosphere system ionosphere plasma. Time this parameter were done underwent large variations. series of these velocities are using ground based In the following report, we used to create convection magnetometers, estimates describe the response map of the day-side of hemispheric energy of the polar ionosphere and night-side magnetic deposition rate using the and thermosphere to the reconnection. When this instruments on board the storm, using data from map is combined with the Polar spacecraft, auroral SuperDARN (Super Dual total electron content (TEC) imaging data from IMAGE Auroral Radar Network), measurement from the satellite and global MHD Madrigal and satellite GPS (Global Positioning simulations [5]. The total orbitdata. System) receivers, features precipitation power gives such as polar cap patches an indication of the increase Madrigal is a database can be observed. These in the neutral density of the for incoherent scatter are islands of high number thermosphere. radar (ISR) systems. The density F region ionospheric ISR is a powerful ground plasma, surrounded by In this study, the state based tool that measures plasma of low density. The vector data (position and various properties of convection of the polar cap velocity) of GRACE satellite

太空|TAIKONG 43 was used to obtain the be discussed in the next • Newtonian gravity thermosphere density section. The following force perturbation of Sun and during the storm on 26 models were used in the Moon. September 2011. The estimation process [4]: orbit of the satellite was at • CSPICE rotational 450 Km altitude with 89° • Spherical harmonic model of Earth with inclination and longitude gravity model of the J2000 as the base of the ascending node as Earth of order and frame and ITRF93 as 251° east of GST. The state degree 50 with the the target frame. vector data was combined inclusion of solid with the force models using tides using first order • Cannon ball radiation sequential batch least- tidal theory. The pressure model with squares estimation process gravity coefficients initial =1.6950. were obtained from 푅 [6] to obtain the drag co- 퐶 efficient of the satellite. This ITU-GRACE16 • NRLMSISE-00 for the was then used to compute [7] with the Earth atmosphere model with the thermosphere density. flattening parameter initial drag co-efficient, The result of this work will of1/298.2572 =2.2 퐶퐷

II. Result

Figure 1 gives us the a strong southward IMF Combining the total parameters of solar winds. before the growth phase electron content (TEC) data About 12:30 UT, there is an of low sub-storms (around from the Global Positioning enhancement of solar wind 16:40 UT and 19:00 UT). System (GPS) receivers flow pressure before the During those sub-storms with the Map Potential Earth’s magnetopause, and period, the electron number technique based on the a second enhancement density is large both in high Super Dual Auroral Radar is observed at 19:00 UT. latitude and low latitude Network (SuperDARN) During this period, the regions (Figure 2a), data, the observational magnitude of magnetic field and the temperature of evolution of polar cap is strong, accompanied by electrons was enhanced ionization parches, islands strong plasma speed. In the and was about twice larger of high number density same figure, the AE auroral than the ion temperature ionospheric plasma in F electrojet indices show (Figure 2b-c). region, can be studied.

44 太空|TAIKONG Figure 1: Parameters of solar winds.

Figure 2: Poker Flat Incoherent Scatter Radar data on 26 Sep 2011. (a) Electron density, (b) Electron temperature, and (c) Ratio of electron temperature to ion temperature.

太空|TAIKONG 45 Figure 3: Evolution of polar cap ionization patches.

Figure 3 shows that there During the storms, strong nightside regions. After is large total electron southward magnetic field the patches cross the content in the dayside in the IMF can cause those polar region, the sub-storm mid-latitude region. streamlines or convection (nightside reconnection) This can be attributed to expand to lower latitude causes the patches to to the solar ultraviolet region. This expansion move back to dayside radiation. The electrostatic can result in the plasma region[2]. potential contour lines on the dayside region. can be treated as the flow This adds more plasma to The plasma velocity is streamlines [1], and the the convection. Figure 3a obtained from the Madrigal electrons or plasma which and Figure 3b show that database. Using the relation is frozen in the magnetic the patches formed in the between the electric field field move along those dayside region cross the due to solar wind and streamlines, like fluids. polar region to enter the the plasma velocity, the magnitude of the electric

46 太空|TAIKONG Figure 4: The magnitude of electric field. The red vectors mean westward and blue vectors means eastward. field can be obtained. and magnetic fields of the estimation process, the This is shown in Figure 4. earth and solar wind, when ground track of the satellite It can be seen that the electric field is strong, the was plotted against the magnitude of electric field plasma speed will be high. corresponding density is high during and after the values for the days 25 and storm. The color of electric For the satellite orbit 26 September, 2011. It can field which is blue in the estimation process, 2 days be seen from the figures 5 figure turns to red. This were chosen. A day before and 6 that there is an overall is related to the electric the storm (25 September, increase in the density of field of solar wind. Red 2011) and the day of the the thermosphere on the color indicates a westward storm (26 September, day of the storm, especially electric field and blue color 2011). Theinitial state vector in the region surrounding indicates an eastward required for the estimation the North Pole. electric field. Since plasma process was obtained from is controlled by the electric the JPL database [1]. After

太空|TAIKONG 47 Figure 5: Atmospheric density along the ground track of the GRACE satellite on the day before the storm.

Figure 6: Atmospheric density along the ground track of the GRACE satellite on the day of the storm.

48 太空|TAIKONG III. Conclusion

Combining the TEC data of density increase: the the neutral velocity. From GPS receivers with the map heating of the neutrals by Figure 2, it can be seen potential technique based the precipitating particles, that the plasma density and on SuperDARN data, it Joule heating due to velocity are higher during can be observed that the enhanced electric field the storm which could polar cap patches from the and momentum transfer explain the rise in neutral dayside regions cross the via transient neutral-ion density. The increase in poles and move towards drag. The Joule heating the neutral density can the nightside, which are is proportional to also be due to diffuse 2 driven back to the dayside ) , where is푒 푛the auroral precipitation, as 푛 푛 (푣⃗ by the sub-storm. The plasma density, 푒 is opposed to inverted V-type − 푢⃗ ⃗ 푛 following mechanisms can the neutral density, 푛 is precipitation [3]. 푛 be attributed to the neutral the ion velocity and is 푣⃗ 푢⃗ ⃗

References

[1] Zhang Q, Zhang B, Lockwood M, et al. Direct Observations of the Evolution of Polar Cap Ionization Patches[J]. Science, 2013, 339(6127): 1597-1600. [2] Sojka J J, Bowline M D, Schunk R W, et al. Modeling Polar Cap F-Region Patches Using Time Varying Convection[J]. Geophysical Research Letters, 1993, 20(17): 1783- 1786. [3] ftp://isdcftp.gfz-potsdam.de/grace/Level-1B/JPL/INSTRUMENT/RL02/2011/ (GRACE data) [4] http://tudat.tudelft.nl/index.html (Orbit determination software) [5] Clausen, L. B. N., Milan, S. E., & Grocott, A. (2014). Thermospheric density perturbations in response to substorms. Journal of Geophysical Research: Space Physics, 119(6), 4441-4455. [6] Vallado, David A. Fundamentals of astrodynamics and applications. Vol. 12. Springer Science & Business Media, 2001. [7] http://icgem.gfz-potsdam.de/tom_longtime

太空|TAIKONG 49 Polar cap patch evolution during a CME driven geomagnetic storm

Yuzhang Ma1, Xiang Deng2, Chao Wei2, Yimin Han2 1 Institute of Space Sciences, Shandong University, Weihai, Shandong, China 2 National Space Science Center, CAS

Abstract

This paper presents cap patches are fully dusk sector and connected observations of polar cap detected. The tongue of the previous patch after patches at the noon section ionization (TOI) was cut by ~10 minutes. By using during the first initial phase storm-enhanced westward CHAIN observation, strong and main phase of a storm convection flow and formed amplitude scintillation is on 7-8 September 2017. By polar cap patch. Due to the observed around polar cap combing the GPS-TEC and suddenly changed IMF By, patch. SuperDARN observations, another polar cap patch the evolution of the polar entered the polar cap from

I. Introduction

1.1. Polar Cap Patches

Patches of ionization are common phenomena in the polar ionosphere. It is like islands of high density ionospheric plasma surrounded by plasma of half the density or less (e.g. Crowley [1996] ). Its spatial size is about hundreds of to thousands of kilometers.

Figure 1: A map of Total Electron Content (TEC)

50 太空|TAIKONG 2.2. Evolution of polar cap patches

During southward IMF, pulled into the nightside nightside reconnection the patches follow the oval on exiting the polar play’switch’roles to form convection pattern cap [eg. Carlson,1994; the patch and allow it exit across the pole from Moen etal.,2006, Zhang the polar cap. day to night and are etal.,2013]. Dayside and

Figure 2: Two static schematic pictures of patches [Zhang et al., Science, 2013 & Dungey, PRL, 1961].

1.3. Observation Instruments

The patches could in the viewable field. GPS the ion density observed be observed in many TEC and total-electron- by ionospheric satellites mechanisms like the all- content map can also can also characterize the sky camera etc., it will be used to observe the distribution of the patch. show the airglow patch polar cap patch, and

1.4. Effects from polar cap patches

The motions of polar variable disturbances over-the-horizon radar cap patches and related to High Frequency (HF) location errors, as well density gradients give radio communications, as disruption and errors

太空|TAIKONG 51 (a) (b)

Figure 3: (a) Polar cap flow structures surrounding an airglow patch [Zou et al., 2015] (b) Rapid moving polar cap patches in TEC map [Zhang et al., 2016] to satellite navigation source of upwelling ions for and communication. Fast accelerations mechanisms moving polar cap patches at greater altitudes which provide an important can eject the ions.

II. Event: Geomagnetic Storm on September 7th, 2017

2.1. Polar Cap Patches: Observations and Results

During the time period of main phases. In our study, Figure 4 is the temporal 7-8 September, an intense we only focused on the variations of IMF conditions geomagnetic storm was first main phase. The time and solar wind parameters, generated with a double period is between 23:00 on including B total, By-GSM main phase. 7th September and 01:00 component, Bz-GSM on 8th September with the component, solar wind These two panels show minimum value of SYM-H speed, ion density and SYM-H and AE index. There reaching -144nT. dynamic pressure. are double intense storm

52 太空|TAIKONG Figure 4: SYM-H and AE index on September 7th-8th, 2017.

In Figure 5 we can see al, 2017, the storm may be before the storm, there that around 23 UT the B triggered by coronal mass exists a tongue of ionization. total, solar wind speed, ejections (CMEs). Around 23 UT, the TOI was density, dynamic pressure cut and formed a polar all increased. According to According to the Map of cap patch. Then the patch the paper of Ercha Aa, et TEC from 21 UT to 24 UT,

太空|TAIKONG 53 Figure 5: IMF conditions and solar wind parameters on September 7th-8th,2017 (From top to

bottom are as followed: Btotal, By-GSM , Bz-GSM, vsolar wind, nion and Qdynamic). connected with a new (TOI) Initially, it is a Tongue of in dusk sector marked with from dusk sector. Ionization (TOI) marked with blue ellipses (Figure 6). the blue circle, it is a strong The following pictures show westward convection flow About ten minutes later, the detailed process of the the strong westward phenomenon. convection flow moved

54 太空|TAIKONG Figure 6: The map of TEC on UT 22:50--22:52 of September 7th-8th, 2017.

Figure 7: The map of TEC on UT 23:06—23:08 of September 7th-8th, 2017.

太空|TAIKONG 55 Figure 8: The map of TEC on UT 23:38-23:40 of September 7th-8th, 2017. toward noon and cut About thirty minutes later, TOI extended from MLT at TOI into polar cap patch the direction of By turned 15 region and connected (Figure 7). to the negative direction, to the previous patch which leaded to the new (Figure 8).

2.2. Ionospheric Scintillation: Observations and Results

In order to have further scintillation receivers and Cambridge Bay, Resolute, recognition of this event, 6 Canadian Advanced Eureka, respectively. besides the SuperDARN Digital Ionosonde (CADI). data, we analyzed the For Cambridge Bay, data from Canadian According to the Resolute, Eureka. All of the High Arctic Ionospheric distribution of CHAIN, we data suggested that Strong Network (CHAIN). The can find that there are amplitude scintillation CHAIN consists of three stations around the was observed around the 25 Global navigation polar cap patch. They are patch. However, multipath satellite system (GNSS) effect should be cautioned.

56 太空|TAIKONG Figure 9: The distribution of CHAIN

Figure 10: The three stations around the polar cap patch

太空|TAIKONG 57 (a)

(b)

58 太空|TAIKONG (c)

Figure 11: The result from CHAIN and the location of satellites ((a):S4 index, Pseudo Range TEC and Carrier noise ratio(C/No) from Cambridge Bay (b) S4 index, Pseudo Range TEC and Carrier noise ratio(C/No) from Resolute. (c) S4 index, Pseudo Range TEC and Carrier noise ratio(C/No) from Eureka)

III. Conclusion

A geomagnetic storm TOI extended from dusk around the polar cap triggered by CME occurred side due to the suddenly patch. However, the at 23:00 UT, September 7th, changed By(positive to multipath effect must be 2017. And the TOI was cut negative) and connected cautioned. The scintillation by the westward convection to the previous polar cap data should be checked to flow and formed polar cap patch. Strong amplitude get the correct S4 and σφ patch. A newly formed scintillation was observed index.

Acknowledgement

Thanks to the organizers and environment, Heinsekman, Lijuan En, for providing us with such a especially for Maurizio Anna Yang, Yu Bai and good learning opportunity Falanga, Li Xinjun, Craig DongJing Bai. Thanks to

太空|TAIKONG 59 all the lectures, tutors and and Lingxin Zhao. Thanks eiscat.se, cdaweb.sci. assistants, especially for to the websites for providing gsfc.nasa.gov and chain. Qinghe Zhang, Yaqi Jin, us with the data, especially physics.unb.ca. Jianjun Liu, Yuzhang Ma for vt.superdarn.org, www.

References

[1] Dungey, J. W. (1961). Interplanetary magnetic field and the auroral zones. Phys.rev.lett, 6(2), 47-48.

[2] Zhang, Qing‐He, Zong, Qiu‐Gang, Lockwood, M., Heelis, R. A., Hairston, M., & Liang, J., et al. (2016). Earth’s ion upflow associated with polar cap patches: global and in situ observations. Geophysical Research Letters,43(5), 1845-1853.

[3] Zou, Y., Nishimura, Y., Lyons, L. R., & Shiokawa, K. (2017). Localized polar cap precipitation in association with nonstorm time airglow patches. Geophysical Research Letters, 44.

[4] Aa E, Huang W, Liu S, et al. Mid‐latitude plasma bubbles over China and adjacent areas during a magnetic storm on 08 September 2017[J]. Space Weather-the International Journal of Research & Applications.

[5] Zhang Q H, Zhang B C, Lockwood M, et al. Direct observations of the evolution of polar cap ionization patches.[J]. Science, 2013, 339(6127):1597-1600.

[6] http://vt.superdarn.org/

[7] http://wdc.kugi.kyoto-u.ac.jp/

[8] https://www.eiscat.se/

[9] http://chain.physics.unb.ca/

60 太空|TAIKONG IONOSPHERE / EISCAT INCOHERENT SCATTER RADARS

Polar Ionospheric Response Observed by EISCAT on 7 September 2017

Han Xiao1, Mingyuan Li1, Ning Zhang1, Foju Wu2, Haoyi Chen3 1 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China 2 National Space Science Center, Chinese Academy of Sciences, Beijing, China 3 School of Science, Nanchang University, Nanchang, China

Abstract

Polar ionospheric response during two significant Solar Flares (SFs) events and an interplanetary coronal mass ejections (ICMEs) on 6 September, 2017 have been presented in this paper. By observing the results of EISCAT radars, we describe the first SF, classified X2.2, peaked at 09:10 UT and the second one, X9.3, which is the most intensive SF in the current solar cycle, peaked at 12:02 UT and a ICME arrived long after these flares at around 23:50 UT on 6 September.

I. Introduction

Solar EUV radiation has a ionospheric response to we analyzed the following decisive impact on the 120– SF has importance not only sets of data: 200 km ionosphere, and a from the fundamental point sudden increase of the EUV of view but also for Space (a) X-ray 0.1–0.8 nm emission during SF causes Weather applications. To flux measured by GOES-13 an abrupt enhancement study the 6 September 2017 (http://satdat.ngdc.noaa. of the ionization that can SFs and to investigate their gov/). last from minutes to hours. effects on the ionosphere, Therefore, study of the

太空|TAIKONG 61 (b) Solar radio emission ~1.5 hr (Figure 1c). The electrojet index rose from San Vito radio maximum of SRB was several times during the spectrograph of Radio recorded at 12:00–12:10 day but did not exceed 700 Solar Telescope Network. UT. The UV flux increased nT (Figure 1f). The high- We used spectrums in up to 4 * 1010(phot. Cm- resolution global storm 18 to 180-MHz band and 2s-1) during the X2.2 flare index SYM/H did not show 1,415-MHz flux. A value of and up to 5.8 * 1010(phot. drastic changes either: It 1,415-MHz frequency is Cm-2s-1) during the X9.3 varied from _6 to +10 nT close to GPS/GLONASS flare. The UV emission (Figure 1g). operating frequency. (ftp:// diminished shortly after http://ftp.ngdc.noaa.gov/ the peak of the X2.2 flare, EISCAT (European STP/space-weather/solar- while after the X9.3 flare Incoherent Scatter data/solarfeatures/solar- the intense UV flux was Scientific Association) radio/rstn-1 second/). recorded during much operates three incoherent longer time (Figure 1a). scatter radar systems, (c) Fifteen-second Shortly after the flare onset, at 224 MHz, 931 MHz SOHO/SEM EUV flux at the UV first diminished but in Northern 0.1–50 nm and at 26-34nm. then increased again up and one at 500 MHz on ( https://dornsifecms. to 5.0 * 1010(phot. Cm-2s-1) , used to study usc.edu/spacesciences- and remained increased the interaction between center/download-sem- for ~2.5–3 hr. the Sun and the Earth as data/; Space Sciences revealed by disturbances Center, University of During the day of 6 in the ionosphere and Southern California). September 2017, the level magnetosphere. The of geomagnetic activity EISCAT UHF system was The space weather remained low (Figure 1d– designed as a tristatic conditions on September g). The solar wind speed radar, that is, three facilities 6th is shown in Figure 1. varied between 480 and that work together. These The first X-class flare of 600 km/s, and no step-like are located in , X2.2 peaked at 09:10 UT, changes were recorded Norway and . and the second one of (Figure 1d). The maximum Recently the remote sites X9.3 peaked at 12:02 UT changes of ±6 nT of the in Finland and Sweden (Figure 1a–1c). The latter Interplanetary Magnetic were converted to the VHF flare was the largest in the Field Bz component were frequency. So, EISCAT current 24th solar cycle and registered from 0 to 2 UT UHF system turned into caused HF radio emission on 6 September 2017 single station radar. that lasted for (Figure 1e). The auroral

62 太空|TAIKONG Figure 1: Variations in solar, interplanetary, and geophysical parameters on 6 September 2017: (a) 15-s average full solar disk EUV 0.1–50 nm (red) and 26–34 (black) nm flux from Solar and Heliospheric Observatory/ solar EUV monitor; (b) X-ray irradiance in the range 0.1–0.8 nm as measured by GOES-13 satellite at 1 AU; (c) 1,415-MHz radio emission measured at San Vito Observatory (1 sfu = 10-22Wm- 2 Hz-1); (d) solar wind speed Vsw; (e) Bz component of the interplanetary magnetic field; (f) auroral electrojet index; (g) SYM/H index. Time resolution is 5 min for solar wind and geophysical parameters, 15 s for the UV, 2 s for the X-ray, and 1 s for the radio emission.

As the Figure 2, the UHF temperature 70~80k, dish used for transmission radar (Tromsø, Norway) 12.5 % duty cycle and 1 and reception. located in 69 .13° N μs – 10 ms pulse length 19.13° E, and it operates with frequency and phase In this paper, we download in the 931 MHz band with modulation capability. the EISCAT data on 6 transmitter peak power 2.0 The antenna is a 32 meter September, 2017 from the MW, antenna gain 48db, cassegrain mechanically EISCAT Schedule website antenna beam width 0.5°, fully steerable parabolic (https://www.eiscat.se/ polarization circular, system schedule/schedule.cgi),

太空|TAIKONG 63 Figure 2: The location and line of sight about the four EISCAT radars.

Then the electron density (Vi) were analyzed by (Guisdap). Guisdap is (Ne), electron temperature using the Grand Unified a general package for (Te) and ion temperature Incoherent Scatter Design designing and analyzing IS (Ti), ion drift velocity and Analysis Package measurements.

II. Observation

The electron density (Ne), September 2017 (Figure 3 (SOD) and also Svalbard electron temperature and Figure 4). The data (SVA) 32m antenna. Some (Te) and ion temperature was from Tromsø (TRO) phenomena was found on (Ti), ion drift velocity (Vi) VHF radar, together with that day. were analyzed by using two remoted receivers the observations on 6 (KIR) and Sodankylä

2.1. Electron Density

Two special moments, time. It is the observation sudden Ne enhancements 9:00 UT and 12:00 UT of TRO VHF radar. Four at 9:00 UT and 12:00 were focused on, because different altitudes were UT corresponding to two solar flare happened selected which were 100 the occurrence of solar on these times. Figure 5 km, 150 km, 200 km, flares. This phenomenon shows the Ne changing with 250 km. There were two happened at all the four

64 太空|TAIKONG Figure 3: Plots of EISCAT Tromsø VHF radar on 6 September 2017.

Figure 4: Plots of EISCAT Svalbard 32m antenna radar on 6 September 2017.

太空|TAIKONG 65 altitudes. The explanation in the ionosphere and the SVA 32m antenna radar is that the solar flares Ne increased. also observed the similar enhanced photoionization phenomenon as shown in Figure 4.

2.2. Electron and Ion Temperature

With the data from TRO altitude of both 200 km and Figure 4 also shows that the VHF radar, there was 250 km but not at 100 km 9:00 UT solar flare did not a Te enhancement and 150 km. So the 12:00 cause the enhancement occurred at 12:00 UT UT solar flare only affected of Te. It was probably (shown as Figure 6). This the Te at higher altitude. because the 9:00 UT enhancement happened at

Figure 5: Electron density variation observed by EISCAT VHF radar on 2017-09-06.

66 太空|TAIKONG Figure 6: Electron temperature variation observed by EISCAT VHF radar on 2017-09-06. solar flare was not strong enhancement of Ti outstanding enhancement enough. (shown as Figure 3). The of Te and Ti (shown as observations from SVA 32m Figure 4). TRO VHF radar also antenna radar had a less detected a similar

2.3. Ion drift velocity

There were two Vi The first one was observed elevation angle of TRO enhancement events. One by TRO VHF radar VHF radar was 30° and was happened at 12:00 UT. (shown as Figure 3). the direction of beam was The other was happened at This enhancement was pointing to the geographic about 23:00 UT before the limited in E region (90-150 north, this ion drift mainly CME arrived. km). Considering that the flowed in a horizontal

太空|TAIKONG 67 (northward) direction at SVA 32m antenna radar. One possible reason a limited altitude range. This indicated that the Vi of the first event is the However, SVA 32m enhancement covered a enhancement of Sq current antenna did not detect this large latitude range. Also which can bring extra event because the location it covered a large altitude heating and conductivity is at higher latitude. range which can be seen enhancement (M. in Figure 3 and Figure 4. Yamauchi et al., 2018). The second event This enhancement was The cause of the second happened at around 23:00 occurred before CME event may be the solar UT was observed both at arrived at earth. energetic particle (SEP) the TRO VHF radar and (M. Yamauchi et al., 2018).

III. Conclusion

There were two solar flares The two flares triggered probably caused by Sq (~9 UT and ~12 UT) and the electron density, current enhancement. one CME arrived (23:50 electron temperature, VHF and SVA radar both UT) on earth on September ion temperature detected ion drift velocity 6th 2017. The observations enhancements. VHF enhancement in large from TRO VHF radar radar detected an ion drift altitude and latitude range. and SVA 32m antenna velocity enhancement It was probably caused by radar were analyzed. limited at E region. It was SEP.

Acknowledgement

Thanks to the organizers learning opportunity and tutors, Craig Heinselman, of The Second APSCO environment to learn Anita Aikio, Carl-Fredrik and ISSI-BJ space science from and discuss with Enell, Antti Kero, Jia Jia for school for providing the domestic and foreign directing and the ISSI-BJ us with such a good scientists. Thanks to our staff for organizing.

68 太空|TAIKONG References

[1] https://en.wikipedia.org/wiki/EISCAT

[2] The lecture presentations related to the 2nd ISSI-BJ & APSCO Science space school with ESCAT in Sanya, China.

[3] Yasyukevich, Y., Astafyeva, E.,Padokhin, A., Ivanova, V., Syrovatskii, S.,& Podlesnyi, A. (2018). The 6 September 2017 X-class solar flares and their impacts on the ionosphere, GNSS, and HF radio wave propagation. Space Weather, 16, 1013–1027. https://doi. org/10.1029/2018SW001932

[4] Yamauchi, M., Sergienko, T., Enell, C.-F.,Schillings, A., Slapak, R., Johnsen, M. G.,et al. (2018). Ionospheric response observed by EISCAT during the 6–8 September 2017 space weather event: Overview. Space Weather, 16,1437–1450. https://doi.org/10.1029/2018SW001937

太空|TAIKONG 69 The variation of electron and ion during substorms and magnetic storms on 7 September 2017

Yu LIANG1, Jun-Yi WANG1, Yu-Chang XUN2, Jia-Wei XIONG3, Yang LI3 1 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China. 2 National Space Science Center, Chinese Academy of Sciences, Beijing, China. 3 Nanchang University, Nanchang, Jiangxi, China.

Abstract

In this paper, we analyzed during 3-12 am and at 8:40 of this day, it can be seen the data of EISCAT VHF pm there was a significant that there were several radar on September 7, increase in the electron substorms in the morning 2017. We found that there density. Comparing the AE and a large magnetic storm was a large ion uptake index and the DST index in the evening.

I. Introduction

Auroral substorms are largest substorms (Ogawa observe electron density, suspected to be the second et al., 2013). The increase electron temperature, ion important process injecting of O+ and H+ (may have temperature and ion drift ionospheric O+ into other ions) concentration is velocity and it provides the themagnetosphere, after quite possible to effect on possibilities to investigate the dayside ionosphere in reaction rates of the upper the relationship between the cleft ion fountain. The atmosphere chemistry electron concentration, ion total nightside auroral zone and cause the variation of upflow and substorm or ion outflow rate depends electron and ion. EISCAT magnetic storms. In this on the size of the substorm, (European Incoherent paper, we reported the increasing by about a Scatter Scientific variation of electron and factor of 10 for both O+ and Association) incoherent ion on 7 September 2017. H+ from the smallest to the scatter radars can

70 太空|TAIKONG Figure 1: Time variations of the ionospheric plasma parameters.

太空|TAIKONG 71 II. Instruments and data

EISCAT (European 19°E), The EISCAT radars ion composition, by fitting Incoherent Scatter measure profiles of theoretical lag profiles Scientific Association) to lag profiles decoded incoherent scatter radars electron density, electron from the received signal located at Tromso(69°N, and ion temperature, and (Verronen et al., 2015). a simple parametrization of

III. Results

Shown as Figure 1, there are three interesting phenomena.

3.1. Increase of ion drift velocity

The first unusual at 3:40, 6:40 and 9:00 phenomenon is the high respectively. speed of upward ion

Figure 2: AE index on 7 September 2017 (http://wdc.kugi.kyoto-u.ac.jp/)

72 太空|TAIKONG 3.2. Decrease of electron density

The second phenomenon rapid decrease of electron also had a great downward is at 6:30 pm to 7:30 pm. density. At the same time, trend. There was a very significant the speed of the ion's drift

3.3. Increase of electron density

After 8:40 of this evening, we saw an increase in electron density.

Figure 3: Magnetic variation on 7 September 2017 over Tromso (https://cdaweb.gsfc.nasa. gov/sp_phys/)

太空|TAIKONG 73 Figure 4: Dst index on 6-8 September 2017 (http://wdc.kugi.kyoto-u.ac.jp/)

IV. Discussions

The high speed of upward at 3:40, 6:40 and 9:00 that the magnetic field ion on 25 September respectively. It can be intensity is also abnormal 2001 has been reported clearly seen that each high- after 10 pm (Figure 3). We by Ogawa et al. (2013). speed ion flow corresponds also look at the DST index They found that the ion to a maximum value of an on 6-8 September 2017. upflow can trigger the AE index. Moreover, at We found that there is a development of substorm night, the high velocity ion magnetic storm began with expansion phase. Because upflow also corresponds the end of 7 September we did not find the aurora to the increase of ionic 2017. Therefore, we think map of this day, we used temperature. that the density disturbance the AE index replaced. after nine points is related On 7 September 2017, the The geomagnetic data to magnetic storms ion drift velocity increased from the same station show (Figure 4).

74 太空|TAIKONG V. Conclusions

1. The high speed velocity ion upflow 2. Large geomagnetic of upward ion also corresponds to storm cause the accompanied by the increase of ionic increase of electron substorm, and temperature. density. at night, the high

Reference

[1] Ogawa Y, Sawatsubashi M, Buchert S C, et al. Relationship between auroral substorm and ion upflow in the nightside polar ionosphere[J]. Journal of Geophysical Research Space Physics, 2013, 118(11):7426-7437.

[2] Verronen, P. T., Andersson, M. E., Kero, A., Enell, C. F., Wissing, J. M., & Talaat,

[3] E. R., et al. (2015). Contribution of proton and electron precipitation to the observed electron concentration in october-november 2003 and September 2005. Annales Geophysicae, 33(17), 381-394.

太空|TAIKONG 75 Polar Ionospheric Response Observed by EISCAT and TEC on 8 September 2017

Ge Chen1, Yuyan Jin1, Honglian Hao1, Liandong Dai2, Hailong Zhao3 1 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China 2 China Electronics Technology Group Corporation No.22 Research Institute, Qingdao, China 3 School of Science, Nanchang University, Nanchang, China

Abstract

Polar ionospheric response been presented in this aurora, dayside particle during a geomagnetic paper. By combining the precipitation and patches’ storm recovery phase and observation of EISCAT, evolution during three a substorm main phase on GPS TEC and SuperDARN period, respectively. 8 Septermber 2017 have radars, we describe the

I. The space weather conditions on 8 September 2017

Figure 1 shows several stations chain. During means that the activities indices of solar and 0000-0400 UT, an intense of auroral electrojet earth activities on 8 negative IMF Bz occurred. strengthen. At the same September 2017. The According to [Kirkwood et time, SYM-H was drop off index from top to bottom al., 1995], the negative Bz and magnetic x-component is interplanetary magnetic will trigger reconnection of high latitude stations field (IMF) strength B, on magnetopause and a fluctuated. During southward component large number of energetic 0400-1200 UT, several Bz, solar wind (SW) particles injects into intermittent Bz appeared velocity, AU and AL index, polar area of Earth which while recovery phase of earth magnetic strength would cause strong this storm. A sequential SYM-H, magnetogram auroral activities. Thus, Bz was observed during X-component of five the differential of AU and 1200-1800 UT. The high latitude magnetic AL was enhanced which differential of AU and AL

76 太空|TAIKONG Figure 1: Several space weather parameters on 8 September 2017: (1) Interplanetary magnetic field B and the southward component Bz, (2) solar wind velocity, (3) provisional AUandAL indices, (4) provisional SYM-H, (5) time series of geomagnetic x-component from five stations chain in Norway. was enhanced intensely again [Yamauchi etal., introduced some activities and the SYM-H decreased 2018]. Our report mainly in these periods.

II. The brief introduction of EISCAT, super DARN radar and GUISDAP

EISCAT (European scatter radar systems, Svalbard, used to study Incoherent Scatter at 224 MHz, 930 MHz the interaction between Scientific Association) in Northern Scandinavia the Sun and the Earth as operates three incoherent and one at 500 MHz on revealed by disturbances

太空|TAIKONG 77 in the ionosphere and that work together. These and 1 µs– 10 ms pulse length magnetosphere. Atthe are located in Finland, with frequency and phase Ramfjordmoen facility (near Norway and Sweden. modulation capability. Tromsø, Norway), it also Recently the remote sites The antenna is a 32 meter operates an ionospheric in Finland and Sweden cassegrain mechanically heater facility, similar to were converted to the VHF fully steerable parabolic HAARP. Additional receiver frequency. So, EISCAT dish used for transmission stations are located UHF system turned into and reception. in Sodankylä, Finland, single station radar. The and Kiruna, Sweden. UHF radar (Tromsø, In this paper, ESR 32m The EISCAT Svalbard Norway) located in 69013 radar and Tromso VHF radar (ESR) is located in N 19013 E, and it operates radar both work with , Norway. in the 930 MHz band with low elevation angle. The The EISCAT Headquarters transmitter peak power location and line of sight are also located in Kiruna. 2.0 MW, antenna gain about the four EISCAT 48db, antenna beamwidth radars have been marked The EISCAT UHF system 0.50, polarization circular, in Figure 2. was designed as a tristatic system temperature radar, that is, three facilities 70~80k, 12.5 % duty cycle The Super Dual Auroral Radar Network (SuperDARN) is an international scientific radar network consisting of 35 high frequency (HF) radars located in both the Northern and Southern Hemispheres. SuperDARN radars are primarily used to map high-latitude plasma convection in the F region of the ionosphere, but the radars

Figure 2: The line of sight about the four EISCAT radars under geomagnetic coordinate system.

78 太空|TAIKONG are also used to study a km in range. Figure 2 is a To get the measured ACF, wider range of geospace single HF radar. it becomes necessary to phenomena including field calculate all measured aligned currents, magnetic GUISDAP (Grand Unified crossed products and reconnection, geomagnetic Incoherent Scatter ambiguity functions. Then storms and substorms, Designand Analysis we need the calculation magnetospheric MHD Package) is a general of theoretical spectra at waves, mesospheric winds package for designing a particular height, which via meteor ionization trails, and analyzing IS carries the information of and interhemispheric measurements. By applying plasma properties (electron plasma convection the full-profile method density, temperature ratio asymmetries. based on the concept of electron and ion and of range-gates to data ion temperature). In the SuperDARN radars operate generated from the model following we formalize the in the HF band between 8.0 , one then fits full-profile analysis as a MHz and 22.0 MHz. In the the plasma parameters by concrete inverse problem. standard operating mode least-squares methods to In this situation, some each radar scans through the chosen measured ACF plasma parameters we 16 beams of azimuthal (autocorrelation function) wanted can be obtained by separation of ~3.24°, with values using known least-squares the inverse a scan taking 1 min to theories about forms of methods. The fitting itself complete (~3 seconds plasma spectra. The is based on ideals derived integration per beam). effects of transmitted pulse from statistical theory. Each beam is divided into forms and post-detection Consequently, we can 75 (or 100) range gates filters are then accounted analyze ionosphere plasma each 45 km in distance, for in various ways by parameters with GUISDAP. and so in each full scan different corrections to the Thus, more detailed the radars each cover 52° signal strengths in the ACF physical phenomena can in azimuth and over 3000 lag estimates. be analyzed.

太空|TAIKONG 79 III. Observation

3.1. An overview by EISCAT

Figure 3: Plots (a-d) of EISCAT Svalbard 32m radar, 42m radar, Tromso UHF radar and VHF radar data on 8 September 2017. From top to bottom in each plot: 5 min averaged values of (1) The log of electron density (Log(Ne)), (2) electron temperature (Te), (3) ion temperature (Ti), (4) the drift velocity of ion (Vi), (5) [O+]/Ne, (6) Log(CO).

80 太空|TAIKONG Figure 3: Plots (a-d) of EISCAT Svalbard 32m radar, 42m radar, Tromso UHF radar and VHF radar data on 8 September, 2017. From top to bottom in each plot: 5 min averaged values of (1) The log of electron density (Log(Ne)), (2) electron temperature (Te), (3) ion temperature (Ti), (4) the drift velocity of ion (Vi), (5) [O+]/Ne, (6) Log(CO).

3.2. The event A during 0000-0430 UT

Figure 4 shows a snapshot radar. During 0000- 0400 present that above. As of TEC which was UT, only VHF radar had we can see, during 0000- observed by superDARN observation data, thus we 0400 UT, VHF was on the

太空|TAIKONG 81 Figure 4: TEC map for event A of superDARN radar on 8 Septermber, 2017. Black lines represent the location and direction of Svalbard 32m and Tromso VHF radars.

as a circle. According to these results, we estimated there appeared an auroral activity around high latitude nightside, but the TEC was the higher or lower latitude region during 0000-0400 enhanced around 70°N but was not which was shown UT.

3.3. The event B during 1000-1230 UT

Figure 3 presents the of sight about the Tromso plasma information in the three EISCAT radars’ VHF radar and ESR 32m dayside. Observed by observation during 0930UT radar and the view of two VHF radar, high electron – 1200UT. For a better SuperDARN radars (HAN density and temperature vision, we show the GPS and PYK) are marked. plasma are located in TEC and convection flow During this event, three the photoionization area. map, with which the line EISCAT radars offer the Plasma near the dayside cusp region are observed by two ESR radars which provide the information along the altitude and latitude. The feature of

Figure 5: TEC map for event B of superDARN radar on 8 Septermber, 2017. Black lines represent the location and direction of Svalbard 32m and Tromso VHF radars.

82 太空|TAIKONG electron with high density Noted that the high ion a characteristic of joule and temperature may be temperature is observed in heating. caused by the dayside low latitude region, where particle precipitation. is also in low altitude. It is

3.4. The event C during 1230-1730 UT

Figure 6 shows a clear observation vison about the evolution and TEC of polar cap patches. about electron Generally, patches are density. The formed near the cusp ion line-of- regions and then evolved sight velocity along the ionospheric observed convection stream lines by EISCAT into the nightside auroral radars also oval modulated by the correspond nightside magnetic tail with the reconnection, and finally convection, returned to the dayside. In indicating that this study, the GPS TEC the patches maps show the TOI, new have the formed patches along the evolution convection stream lines, velocity patches disappearing comparable in the nightside, to the velocity respectively. There are find of ionospheric correspondence between convection. the EISCAT radars’

Figure 6: TEC map for event C of superDARN radar on 8 Septermber 2017. Black lines represent the location and direction of Svalbard 32m and Tromso VHF radars.

太空|TAIKONG 83 IV. Conclusion

In this paper, we present the a substorm main phase on radars,aurora, dayside polar ionospheric response 8 Septermber 2017. With particle precipitation and during a geomagnetic the observation of EISCAT, patches’ evolution have storm recovery phase and GPS TEC and SuperDARN been described.

Acknowledgement

Thanks to The Second from and discuss with Anita Aikio, Carl-Fredrik APSCO and ISSI-BJ space the domestic and foreign Enell, Antti Kero, Jia Jia for science school for offering scientists. Thanks to our directing and the ISSI-BJ a rich opportunity to learn tutors, Craig Heinselman, staff for organizing.

References

[1] Kirkwood, S., & Osepian, A. (1995). Quantitative studies of energetic particle precipitation using incoherent scatter radar. Journal of Geomangetism and Geoelectricity, 47(8), 783-799. http:// doi.org/10.5636/jgg.47.783.

[2] Yamauchi, M., Sergienko, T., Enell, C.-F., (2018). Ionospheric Response Observed by EISCAT During the 6-8 September 2017 Space Weather Event: Overview. Space Weather, 16. http:// doi.org/10.1029/2018SW001937.

84 太空|TAIKONG Three types Enhanced Electron Density phenomenon of Ionosphere in 9 September 2017: EISCAT Observations

Yu Hong1, Pachara Srimuk2, Nattawat Chantasen2, Ivan Manay3, Dagva Baatarkhuu4 1. National Space Science Center, CAS, Beijing, China, 2. King Mongkut’s University of Technology North Bangkok, Thailand 3. Geophisical Institute of Peru, Peru 4. Institute of Astronomy and Geophysics, MAS, Mongolian

We present the ionospheric important parameters when The first phenomenon of electron density observed considering changing in the increasing of electron by the EISCAT VHF radar in ionospheric is the electron density is the daytime Tromso (69o35’N, 19o14’E) density. The basic equation period due to the first term on 9th September 2017. can be described as follow: q of the equation, which is This is a period shortly after also the cause of the daily the X-ray flares occurred ∂Ne/∂t=P-L- ×(NV) variation. When the neutral and the interplanetary atmosphere is ionized ∇ Coronal Mass Ejections where the Ne is the electron by the solar ultraviolet (ICMEs) attacked Earth. density. P and L mean the radiation, the electron It is worth mentioning production and loss rate of density increases and that the variation of the electron number density, the ionosphere begin to electron density on 9th respectively. The third term form. The statistical results Sept. 2017 has some is the divergence of the obtained by ionosonde or significant special features plasma velocity flux, as other ionosphere detected from the typical day-to-day known as the transportation instruments all show variation. One of the most item. that the magnitude of

Figure 1: EISCAT VHF-radar electron density result on 9th September 2017 in Tromso.

太空|TAIKONG 85 Figure 2: EISCAT VHF-radar ion drift velocity result on 9th September 2017 in Tromso. daytime electron density the transportation term, confirmed by Figure 2, the is positively correlated with which comes the third results of ions drifts. We find the intensity of the solar term of the equation. a large negative velocities flux, these results can be First let’s talk about the (blue region) at the same found in the VHF radar first mechanism: particle region synchronous, which results from different days. precipitation. During 00LT means a big amount of to 03LT on 9th September, ions moved to the radar, During nighttime when the a large increase of electron in other words, toward the photo-chemical process number is observed at the ground, that is why we driven by the solar radiation height of around 100km, see “precipitation”. We ceases, ionosphere also referred to as the E studied much further, with loses the direct source of region. This is due to the both the AE index and the electron generation. The particle sedimentation of local magnetic field results electron density at the the polar region caused as well as the aurora night side Ionosphere is by some space weather observation, the process mainly supplemented by events, which can be becomes clear: the plasma

Figure 3: Aurora observed in Alaska on 9th September 2017.

86 太空|TAIKONG production of plasma, the accumulation of electrons in this height is also the result of the dayside electron transport. Also with the result of ion drift velocity, we found that the ion velocity has severe positive and negative fluctuations in the same region simultaneous. After Figure 4: Aurora observed in Alaska on 9th September 2017. the aurora occurs, there will be small plasma patch traveled from the day side The third phenomenon in structures in the polar to the night side polar which electron density is region and will move at region along the magnetic significantly enhanced is night. The result is the lines finally accumulated at also in the nighttime during positive and negative the E-region ionosphere, 18LT to 00LT, an increase fluctuations of the velocity causing a large disturbance of density recorded in the observed by the radar. of the local magnetic field. F region between 200 and 400 kilometers. Without

Figure 5: Electron and ion temperature observed in Alaska on 9th September 2017.

太空|TAIKONG 87 Here are more details temperature (green color) of electrons is slightly of the electron and ion of electrons and a relative higher than the ions. This temperature results high temperature (purple interesting phenomenon showed in Figure 5. The color) of ions in the same is wealth studying in the enhanced density event region. Although they are at future. leads to a relative low different heights, the height

Acknowledgements

This work was supported operate the software and Enell. We also thank by the EISCAT and the to analysis the result with ISSI-BJ for allowing us to Madrigal database center. EISCAT data, including study and perform these We thank all those people Craig Heinselman, Anita experiments in the space who helped us to install and Aikio, and Carl-Fredrik summer school.

88 太空|TAIKONG Observation Results of Polar Ionosphere by ESICAT on Sep.10, 2017

Changjun Yang1, Guowei Wang2, Xiangyu Wang3, Song Yang4, Linqi Zeng

1. Institute of Geology and Geophysics, CAS, China 2. China University of Geosciences, China 3. Shandong University, China 4. China Research Institute of Radiowave Propagation, China

Abstract

As required, we get the interesting discovery of NASA and SuperDARN. data of ESICAT radar about polar ionosphere. It seems some thing system on Sep.10, 2017 on We also combined happened during that day the Internet, and running other observations from but we don’t have a clear the GUISDAP to process terrestrial geomagnetic understanding about the the data gives us some filed, IMF data from satellite results.

I. Introduction

EISCAT (European in the ionosphere and Longyearbyen, Norway. Incoherent Scatter magnetosphere. At the The EISCAT Headquarters Scientific Association) Ramfjordmoen facility (near are also located in Kiruna. operates three incoherent Tromsø, Norway), it also scatter radar systems, operates an ionospheric EISCAT is funded and at 224 MHz, 931 MHz heater facility, similar to operated by research in Northern Scandinavia HAARP. Additional receiver institutes and research and one at 500 MHz on stations are located councils of Norway, Svalbard, used to study in Sodankylä, Finland, Sweden, Finland, , the interaction between and Kiruna, Sweden. China and the United the Sun and the Earth as The EISCAT Svalbard Kingdom (the EISCAT revealed by disturbances radar (ESR) is located in Associates). Institutes in

太空|TAIKONG 89 Figure 1: .Solar physical conditions for 8-10 Sep. 2017. other countries also Software to process data been quiet about terrestrial contribute to operations, of EISCAT.The reason why geomagnetic field ,and no including Russia, , we choose Sep.10, 2017 thing happened in polar Germany and . is that we are required to ionosphere during that day. research this day’s polar So all following discussion We used the GUISDAP ionosphere and before is just about that day, (Grand Unified Incoherent several days , there was meanwhile it is not only Scatter Design and a CME event happened. focused on the EISCAT Analysis Package) But well,It seemed to have data.

II. Result of data processing

The interplanetary physical 21h UT Sep. 07, 2017 time.The data comes from conditions shown in and IMF (Interplanetary NASA (OMNI program). Figure 1 provides some Magnetic Field) Bz The Dst index intensely information that there is a component has a sharp decrease more than 100 electric increase at about decrease at the same nT simultaneously and

90 太空|TAIKONG Figure 2: Some Changes in some geomagnetic indices on September 10, 2017. lasts more than 24 hours to (Kyoto University) shown high latitudes.This conveys recovery.That means there in Figure 2 gives some very important information: is a big storm happens.But interesting information the environment of the when time goes to Sep.10, about magnetic field interplanetary space must the lack of IMF data means of earth.It can be seen have undergone some we can’t know what occurs from Figure 2 that the changes, which has led to in interplanetary space. STM-H index produces a the response of the Earth's There is no useful message decrease of about 25 nT magnetic field to it. we can get just form Bx around 16 o'clock, while component on Sep.10. the AE index grows slowly EISCAT has four at an earlier time. On the experimental data Naturally, we trend our evening of the day, the AE available for analysis on focus on the magnetic index produced dramatic this day, namely Bella, field of earth. The data of fluctuations, which Beata, Folke and Ipy. The SYM-H index , AL and AU meant that geomagnetic positional modes of the four index provided by WDC substorms occurred in experiments are given in

太空|TAIKONG 91 Figure 3: The Positional modes of the four experiments.

Figure 3. The time range 69.5°N and 19.14°E. As electrons and ions. The covered is 17:00-21:00, can be seen from Figure 4, electron temperature in 9:00-17:00, 0:00-18:00 and at around 8:25UT, an the channel can be seen 18:00-24:00. Although their electronic channel from to increase significantly, detection positions are all 250 km height to 100 km whether it is time or space in the high latitude area, the height appeared, which contrast. This shows that detection modes are not the lasted about 5 minutes. the electrons heat the same, and the coverage In this dark red band, the surrounding electrons by points are different, so they electron density is about friction during the falling are described separately 1011 per cubic meter from process, but the energy below. top to bottom.Interestingly, is too much relative to the the drift velocity of the ions. Low, can not play a Figure 4 shows the results ions did not produce significant role.The flipping of the Beata experiment. much change at this of the electron temperature The Beata mode uses moment. This shows that at around 18:50 is a fixed antenna with a the movement of electrons considered to be caused direction along the earth's from high to low does not by the difference in the magnetic field lines. The give momentum changes position of the sun caused experiment experienced 4 to the ions, which may be by day and night changes. hours, the detection height due to the elastic collision was 50-650km, and the caused by the excessive The results of the experimental position was mass difference between experimental Folke are

92 太空|TAIKONG Figure 4: Result of Beata Experiment. shown in Figure 5. The time-related phenomenon During the period of 0: 00 experiment took place in is believed to be due to - 06: 00UT, we can see that Svalbard and lasted 18 the direct solar radiation, the height of the low electron hours. The stratification resulting in the westward density layer at 0 - 200 km of the earth's ionosphere ion drift toward the polar height gradually becomes derived from Chapman's region at noon. Combined thinner with time, which is theory can be clearly with the parameters of considered as a reflection seen in Figure 5. The ion various experiments, it of the disappearance of the drift velocity increased is confirmed that this is E layer and F2 layer of the significantly at almost full a normal ionospheric ionosphere at night. detection height between phenomenon and should 10: 00 and 15: 00 UT, while have nothing to do with other parameters did not the physical phenomena change significantly. This in interplanetary space.

太空|TAIKONG 93 Figure 5: Result of Folke Experiment.

94 太空|TAIKONG III. Conclusion

In this report, EISCAT solar wind disturbance much value, including the radar data on September event has been found, specific parameters of 10, 2017 are processed two characteristics from each test and radar are and analyzed briefly in the four results are clearly given in the appendix after combination with satellite described, and the the report. data and ground magnetic results of the remaining survey data. Since no clear experiments are not of

Acknowledgements

Thanks to the professors various parameters of the MAGNET. Thanks to NASA and teaching assistants Earth's magnetosphere. for the data of interplanetary of summer school for their Thank you for the ground parameters. careful teaching. Thanks magnetic survey data to Kyoto University for the provided by INTER

Appendix

Table 1: Specific parameters and modes of various tests of EISCAT radar.

太空|TAIKONG 95 Figure 6: Result of Bella Experiment.

96 太空|TAIKONG Figure 7: Result of Ipy Experiment.

太空|TAIKONG 97 EFFECTS ON SATELLITES AND GROUND-BASED INFRASTRUCTURES

Introduction to the topic

Toyafel Ahammad, Bangladesh Space Research & Remote Sensing Organization, Bangladesh Abdul Kader, Bangladesh Space Research & Remote Sensing Organization, Bangladesh

I. Introduction

Space Weather is a radiation (radio waves, electromagnetic radiation term which has become infra-red, light, ultraviolet, travels at the speed of light accepted over the past X-rays), and as energetic and takes about 8 minutes few years to refer to a electrically charged to move from Sun to Earth, collection of physical particles through coronal whereas the charged processes, beginning at mass ejections (CME) particles travel more slowly, the Sun and ultimately and plasma streams. The taking from a few hours to affecting human activities particles travel outwards several days to move from on Earth and in space. as the solar wind, carrying Sun to Earth[1][2]. The Sun emits energy, as parts of the Sun's magnetic flares of electromagnetic field with them. The

II. Requirement of Space Weather Forecasting:

Since space weather very complex. Nowaday’s weather more accurately. causes harm to the earth different space research To forecast space weather, atmosphere, it is necessary organization starts to the following knowledge is to forecast space weather. forecast about space. But essential: Forecasting space weather still a lot of research is is not a simple way but required to forecast space

98 太空|TAIKONG • Solar storm and its days by analyzing the • Effect and deep electric impacts on Earth; observed data of the charging with models sun, interplanetary and and software; • The effects of geospace; space weather • 3 steps of impacts of events on satellites • Assess the SID effect, solar storms (Flare and or communication CME propagation, Coronal Mass Ejection); systems; Single Event Effect, satellite drag, surface • Effects of SID, SPE, • Forecast the condition charging; GMS, REE. of geospace of following

III. 3 steps of impacts of solar storms (Flare and Coronal Mass Ejection)

1. X-ray Flare and Sudden of CME and Polar Cap atmosphere, ionosphere Ionospheric Disturbance Absorption. storm and Relativistic on Earth. Electron Enhancement at 3. GeoMagnetic Storm, GEO (outer radiation belt) 2. Solar Proton Event plasma injection near occurred after CMEs reach caused by Flare or shock GEO and aurora belt, Earth. density increase in upper

IV. Effects of SID, SPE, GMS, REE

1. During SID the electron system may be affected or to form current pulses that density of ionosphere will knocked out. is harmful to the devices. increase especially in This is Single Event Effect the D-layer, which lead 2. During SPE, energetic (SEE). Single Event Upset to intense absorption of protons deposit energy in (SEU) is a kind of SEE. Due radio signals and short- semiconductor devices to SEU the logical state of wave fade. Thus the High- and produce electron-hole device changes. frequency communication pairs. Electron-hole pairs are collected by electrodes

太空|TAIKONG 99 3. During GMS, the particles in magnetotail are 4. During REE, relativistic energetic particles that accelerated and injected electrons of outer radiation precipitate into the into near GEO space, belt penetrate MEO/GEO ionosphere add energy and charged particles spacecrafts’ surfaces, in the form of heat that precipitate into aurora accumulate on cables can change distribution belt. The plasma interacts and computer chips, and of density in the upper with spacecraft surface, develop electric field. atmosphere, causing extra causing surface charging This is deep dielectric drag on LEO satellites. effect. charging or inner charging. Due to geomagnetic field It may produce harmful disturbances, charged discharges.

V. Artificial prediction of solar events and activity indexes

1. Summarize the solar 2. To predict Flare, we to forecast when they will activity, geospace consider the active regions’ arrive at Earth and which condition and geomagnetic area, position, magnetic level of GMS they may activity of the past 24 field classification and cause. hours. Based on data from levels of flares produced. interplanetary satellites, 5. To predict F10.7 GEO satellites and ground 3. To predict SPE’s start index, we consider the observation, Predict F10.7, time, level and duration, we number, appearance, Ap and probabilities of 4 consider the flares’ level, disappearance, and kinds of space weather occurrence of CME and flare production of active events (Flare, Solar Proton CME’s arrival time. regions on solar visible Event, GeoMagnetic Storm disk and solar rotation. and Relativistic Electron 4. To predict GMS and Enhancement) for the next Ap index, we consider the 6. Statistical Models can be three days. sources of disturbed solar used to forecast the long- wind in geospace, like term trends of F10.7 and CME and Coronal Hole, Ap.

100 太空|TAIKONG VI. Index of Space Weather Events:

Table 1: Solar Activity

Level Peak X-ray flux Very Low Under C1.0 class Low C class Moderate 1-4 peaks between M1.0 and M4.9 High More than 5 peaks between M1.0 and M4.9 or 1-4 peaks between M5.0 and X9.9 Very High More than 5 peaks between M5.0 and X9.9 or peaks above X10.0

C1.0 flux = 1.0e-5 w/m2 M1.0 flux = 1.0e-4 w/m2 X1.0 = 1.0e-3 w/m2

Table 2: Geomagnetic Activity

Level KpIndex Quiet Kp<3 Unsettled Kp=3 Active Kp=4 Minor Storm Kp=5 Moderate Storm Kp=6,7 Major Storm Kp=8 Extended Storm Kp=9

Table 3: Solar Proton Event

Level Flux of GEO>10MeV protons Quiet Flux<1.0 Minor 10≤ Flux<100 Moderate 100≤ Flux<1000 Major 1000≤ Flux<10000 Extended Flux≥10000

太空|TAIKONG 101 Table 4: Relativistic Electron Enhancement (REE)

Level Daily cumulative fluence of GEO high energy (>2MeV) electrons Quiet Flux<1.0e8 Minor Storm 1.0e8≤ Flux<1.0e9 Moderate Storm 1.0e9≤ Flux<3.0e9 Major Storm Flux≥3.0e9

VII. Conclusion:

Space weather forecasting earth atmosphere as well is very new issue for us, is very important to as to know how this storm extensive study is required know the effect of solar is related to the climate to forecast the space magnetic storms to the change of earth. Since this weather more accurately.

References

[1] Class Lecture of the 2nd APSCO and ISSI-BJ Space Science School

[2] Natural Resources Canada]

[3] National Aeronautics and Space Administration]

[4] Space Weather Forecasting: A Grand Challenge

[5] H.J. Singer, G.R Heckman, and J.W. Hirman

102 太空|TAIKONG Flare Forecast & SID Analysis and Solar Proton Event (SPE) Forecast

Yi-Wun Chen, National Central University, Taiwan

I. Flare Forecast

When the sun was active the area of active region complexity of sunspots, we or some regions of the sun was, the more probability can make the short-term were active, the flare or the flare had. Also the more forecast of the next three the CME might be erupted complex the sunspot was, days about the solar flare. from the sun. A flare is the more probability the an explosive release of flare had. energy stored in the solar atmosphere in and above Depending on the area active regions. The bigger of active region and the

Figure 1: Solar flare productivity in relation to the area of activr region (left) and to the magnetic class.

太空|TAIKONG 103 Figure 2: Sudden Ionospheric Disturbance (SID).

II. Sudden Ionospheric Disturbance (SID) analysis

SID is a disturbance to often increase significantly, region, is likely to intensify the ionospheric election sometimes by two, three, or and thicken as very density profile and more orders of magnitude. short wavelength energy disturbance its total Then, traveling at light penetrates and produces electron content during a speed, arrive at Earth in enhanced ionization. solar flare or series of flares. about 8 1/3 minutes. These changes affect When Flares and fast CMEs propagation conditions happen, X ray, visible, and At the Sudden Ionospheric throughout the radio extreme ultraviolet (EUV) Disturbance, the lower frequency spectrum. It may which emission from flares ionosphere on Earth’s lead to radio blackout. sunlit side, especially the D

III. Solar Proton Even (SPE) Forecast

Some energetic particles of them are protons. The Event (SPE). This event ejected with relativistic observators at GEO found may cause an anomalies speeds near a flare site an enhancement of the flux called single particle arrive the Earth after 30 of energetic protons, which effect or affect the radio minutes. More than 90% is called the Solar Proton communications.

104 太空|TAIKONG Figure 3: Solar Proton Event (SPE).

The events can distinguish events, which is produced CME. The other one is the to three types. One is from flare. One is Gradual combined one. impulsive short-duration events, which is from

Figure 4: Solar Proton Event (SPE).

References

[1] Knipp, D. J.; Gross, N. A. (2011). Understanding Space Weather and the Physics Behind It.

[2] https://www.solarmonitor.org/

太空|TAIKONG 105 Satellite Drag Analysis

Fredy Arturo Calle Bustinza, Space Agency of Peru, Peru

I. Introduction

One of the principal means that during high Drag acceleration is related considerations to keep solar activity the solar to F10.7. The F10.7 cm the satellite orbit, is taking extreme ultraviolet (EUV) solar flux or F10.7 is, along account on drag and solar radiation heats and with sunspot number, one activity. Around the world, expands Earth’s upper of the most widely used satellite orbit operators atmosphere, therefore, the indices of solar activity. are continually monitoring upper atmosphere’s neutral Its applications include values referred about solar density increases satellite as a simple activity level activity and geomagnetic drag and associated orbital indicator, as a proxy for activity, principally focusing decay rate. It means, when other solar emissions or on: Kp and Ap. the Sun is quiet, satellites quantities which are more in LEO orbit have to boost difficult to obtain, and also First, drag is a force their orbits approximately as a commonly available which is acting opposite about four times per year datum for antenna to the direction of motion. to countervail atmospheric calibration. This same force acts on drag, but when solar spacecraft and objects activity is at its greatest A 10.7 cm solar flux flying in the space over, satellites would have measurement is a environment, in addition to be maneuvered every determination of the this force has a significant 2-3 weeks to maintain strength of solar radio impact on spacecraft in low their orbit. In addition, emission in a 100 MHz- Earth orbit (LEO). interactions between the wide band centered on solar wind and Earth’s 2800 MHz (a wavelength The solar activity presents magnetic field during of 10.7 cm) averaged over variable behavior and geomagnetic storms can an hour. It is expressed in influences on thermosferic increase drag on satellites. Solar flux units (sfu), where density levels and the 1 sfu = 10-22Wm-2Hz-1. thermal environment. It

106 太空|TAIKONG Figure 1: Drag acceleration.

Drag acceleration is on the geomagnetic activity value of 9 means extreme related to F10.7 index. measured at the location of geomagnetic storming. As F10.7 increases, drag the magnetometer, which acceleration increases too. measures the maximum Therefore, the K-index, and deviation of the horizontal by extension the Planetary In the same way, the component of the magnetic K-index, are used to Kp-index is the global field at its location and characterize the magnitude geomagnetic activity report this. The global Kp- of geomagnetic storms. Kp index that is based on index is then determined is an excellent indicator 3-hour measurements with an algorithm that puts of disturbances in the from ground-based the reported K-values of Earth’s magnetic field and magnetometers around every station together. The it is used to decide whether the world. Each station is Kp—index ranges from 0 to geomagnetic alerts and calibrated according to 9 where a value of 0 means warnings need to be issued its latitude and reports a that there is very little for users who are affected certain K-index depending geomagnetic activity and a by these disturbances.

太空|TAIKONG 107 The table below shows Estimated 3-hour Planetary Kp-index ranging from the values used by The Kp=0 to Kp=9.

Kp G-scale Geomagnetic Auroral activity Average latitude frequency 0 G0 66.5° or higher Quiet 1 G0 64.5° Quiet 2 G0 62.4° Quiet 3 G0 60.4° Unsettled 4 G0 58.3° Active 5 G1 56.3° Minor storm 1700 per cycle (900 days per cycle) 6 G2 54.2° Moderate storm 600 per cycle (360 days per cycle) 7 G3 52.2° Strong storm 200 per cycle (130 days per cycle) 8 G4 50.1° Severe storm 100 per cycle (60 days per cycle) 9 G5 48.1° or lower Extreme storm 4 per cycle (4 days per cycle)

Table 1: Values used by The Estimated 3-hour Planetary Kp-index ranging from Kp=0 to Kp=9.

The other index considered value is obtained by the 3-hour Kp-values to ap- for satellite drag analysis averaging the eight 3-hour values. is: the Ap-index, which one values of ap for each day. provides a daily average To get these ap-values, The tables below will let level for geomagnetic first is necessary to convert you convert the Kp-values activity. This Ap-index to ap values.

108 太空|TAIKONG Kp Kp in Ap G-scale Kp Kp in ap G-scale decimals decimals 0o 0,00 0 G0 5- 4,67 39 G1 0+ 0,33 2 G0 5o 5,00 48 G1 1- 0,67 3 G0 5+ 5,33 56 G1 1o 1,00 4 G0 6- 5,67 67 G2 1+ 1,33 5 G0 6o 6,00 80 G2 2- 1,67 6 G0 6+ 6,33 94 G2 2o 2,00 7 G0 7- 6,67 111 G3 2+ 2,33 9 G0 7o 7,00 132 G3 3- 2,67 12 G0 7+ 7,33 154 G3 3o 3,00 15 G0 8- 7,67 179 G4 3+ 3,33 18 G0 8o 8,00 207 G4 4- 3,67 22 G0 8+ 8,33 236 G4 4o 4,00 27 G0 9- 8,67 300 G4 4+ 4,33 32 G0 9o 9,00 400 G5

Table 2: Conversion of the Kp-values to ap values.

II. Simulation drag analysis

For our simulation, the data selected for our analysis were:

Date F10.7 Ap September 7, 2017 129 36 September 8, 2017 117 108 September 9, 2017 107 6

Table 3: Data selected for the simulation drag analysis.

太空|TAIKONG 109 Figure 2: Space Radiation Effect Analysis tool

The simulation tool used It is very important to passes through the is: “Space Radiation Effect highlight these important atmosphere. In addition, Analysis”, in order to obtain effects: as satellite drops in altitude some important data and its speed increases. In the graphs from analysis about • Satellite drag makes a following picture below it drag effects on satellites. non-circular orbits more is possible to notice these circular as the satellite effects:

Figure 3: Effects of the satellite drag.

110 太空|TAIKONG In the following picture, Here is being evaluated is going to be compared some data and graphs how these parameters is three consecutive days about altitude vs days are affecting on the satellite with different values of presented: drag. In this simulation it F10.7 and Ap.

Figure 4: Data on altitude vs days.

III. Simulation's conclusion

In Figure 5, it is possible to which indicates quite level of the three satellites, in see the satellite orbit decay of geomagnetic activity and the Figure 6, it can be simulation: its satellite decay would be observed how fast the very slow. satellites will decay toward For example, on September Earth in function of number 8, 2017, Ap = 108, which Simulation performed of days. Summarizing, the indicates a moderate level for September 7, 2017, more altitude, the more of geomagnetic storm, whose values are: F10.7 number of days. therefore satellite decay = 129, and Ap = 36. Thus, would be quick. according to Ap level, a Minor geomagnetic storm On the other hand, on is happening. If these September 9, 2017, Ap=6, conditions were maintained

太空|TAIKONG 111 Figure 5: Satellite orbit decay simulation.

Figure 6: Speed of the satellite orbit decay.

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Participants

Tofayel Ahammad SPARRSO, Bangladesh Yang Li Nanchang University, China Anita Aikio University of Oulu, EISCAT, Finland Gang LI University of Alabama in Huntsville, USA Dagva Baatarkhuu Mongolian Academy of Sciences, Mongolia Yu Liang Institute of Geology and Geophysics, CAS, China Yu Bai APSCO, China Jianjun Liu Polar Research Insitute of China, China Dongjin Bai ISSI-BJ, China Rui Liu University of Science and Technology, China Qingjiang Bai NSSC, China Siqing Liu National Space Science Center, CAS, China Amarjargal Bat-Erdene MAS Geomagnetic, Mongolia Bingxian Luo National Space Science Center, CAS, China Thomas Berger University of Colorado at Boulder, USA Yuzhang Ma Shandong University, China Roger-M. Bonnet ISSI, Switzerland Xuejie Meng National Space Science Center, CAS, China Fredy Arturo Calle Bustinza Space Agency of Peru, Peru Seyed M. S. Mirsane Iranian Space Agency, Iran Nattawat Chantasen KMUTNB, Thailand Yong Ren National Space Science Center, CAS, China Ge Chen IGG, CAS, China Edwar I. M. Salazar Jicamarca Radio Observatory, Peru Haoyi Chen Nanchang University, China Ebrahimi M. Seyedabadi APSCO, China Yi-Wun Chen National Central University, Taiwan Pugazhenthi Sivasankar Delft University of Technology, Netherlands Shanqiang Chen National Space Science Center, CAS, China Pachara Srimuk KMUTNB, Thailand Peng-Fei Chen Nanjing University, China Weiwei Tang National Space Science Center, CAS, China Liandong Dai CRIRP, China Jonas Thurig Embassy of Switzerland, China Ismail Hakki Demirhan TUBITAK UZAY, Turkey Anders Tjulin EISCAT Scientific Association, Sweden Xiang Deng National Space Science Center, CAS, China Junyi Wang Institute of Geology and Geophysics, CAS, China Zheyi Ding China University of Geosciences, China Guowei Wang China University of Geosciences, China Zonghua Ding CRIRP, China Xiangyu Wang Shandong University, China Lijuan En ISSI-BJ, China Rui Wang National Space Science Center, CAS, China Carl-Fredrik Enell EISCAT Scientific Association, Sweden Chao Wei National Space Science Center, CAS, China Maurizio Falanga ISSI-BJ, China Siyuan Wu China University of Geosciences, China Alvaro Gimenez Spanish National Research Council, Spain Tsung-Yu Wu National Central University, Taiwan Chaoran Gu China University of Geosciences, China Fuju Wu National Space Science Center, CAS, China Yimin Han National Space Science Center, CAS, China Ji WU National Space Science Center, CAS, China Xiuhong Han Hebei GEO University, China Han Xiao University of CAS, China Honglian Hao IGG, CAS, China Jiawei Xiong Nanchang University, China Craig Heinselman EISCAT Scientific Association, Sweden Yaodong Xu China University of Geosciences, China Meisam Honari Jafarpour Iranian Space Agency, Iran Jiyao Xu National Space Science Center, CAS, China Yu Hong National Space Science Center, CAS, China Mengjiao Xu USTC, China Huidong Hu National Space Science Center, CAS, China Yuchang Xun National Space Science Center, CAS, China Qiang Hu University of Alabama in Huntsville, USA Changjun Yang Institute of Geology and Geophysics, CAS, China Jia Jia Sodankylä Geophysical Observatory, Finland Song Yang CRIRP, China Wu Jian CRIRP, China Anna Yang ISSI-BJ, China Xiangqun Jiang APSCO, China Tianjiao Yuan National Space Science Center, CAS, China Yaqi Jin University of Oslo, Norway Lingqi Zeng Institute of Geology and Geophysics, CAS, China Yuyan Jin IGG, CAS, China Rongyu Zhang National Space Science Center, CAS, China Abdul Kader SPARRSO, Bangladesh Qinghe Zhang Shandong University, China Antti Kero Sodankylä Geophysical Observatory, Finland Ning Zhang Institute of Geology and Geophysics, CAS, China Karl-Ludwig Klein Obs. de Paris, LESIA&Obs. de Meudon, Lingxin Zhao Shandong University, China France Hailong Zhao Nanchang University, China Bugra Kocaman Tubitak Uzay, Turkey Biqiang Zhao Institute of Geology and Geophysics, CAS, China Hannah Laurens Lancaster University, UK Yuhao Zhou Nanjing University, China Dongni Li China University of Geosciences, China Ivan Zimovets ISSI-BJ, IKI, China, Russia Mingyuan Li IGG, CAS, China Yenan Zou National Space Science Center, CAS, China