Study on Effect of Radiative Loss on Waves in Solar Chromosphere
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On the Solar Chromosphere Observed at the Limb with Hinode
The Astrophysical Journal, 719:469–473, 2010 August 10 doi:10.1088/0004-637X/719/1/469 C 2010. The American Astronomical Society. All rights reserved. Printed in the U.S.A. ON THE SOLAR CHROMOSPHERE OBSERVED AT THE LIMB WITH HINODE Philip G. Judge1 and Mats Carlsson2 1 High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307-3000, USA 2 Institute of Theoretical Astrophysics, P.O. Box 1029, Blindern, N-0315 Oslo, Norway Received 2010 March 8; accepted 2010 April 8; published 2010 July 21 ABSTRACT Broadband images in the Ca ii H line, from the Broadband Filter Imager (BFI) instrument on the Hinode spacecraft, show emission from spicules emerging from and visible right down to the observed limb. Surprisingly, little absorption of spicule light is seen along their lengths. We present formal solutions to the transfer equation for given (ad hoc) source functions, including a stratified chromosphere from which spicules emanate. The model parameters are broadly compatible with earlier studies of spicules. The visibility of Ca ii spicules down to the limb in Hinode data seems to require that spicule emission be Doppler shifted relative to the stratified atmosphere, either by supersonic turbulent or organized spicular motion. The non-spicule component of the chromosphere is almost invisible in the broadband BFI data, but we predict that it will be clearly visible in high spectral resolution data. Broadband Ca ii H limb images give the false impression that the chromosphere is dominated by spicules. Our analysis serves as a reminder that the absence of a signature can be as significant as its presence. -
Our Dynamic Sun: 2017 Hannes Alfvén Medal Lecture at the EGU
Ann. Geophys., 35, 805–816, 2017 https://doi.org/10.5194/angeo-35-805-2017 © Author(s) 2017. This work is distributed under the Creative Commons Attribution 3.0 License. Our dynamic sun: 2017 Hannes Alfvén Medal lecture at the EGU Eric Priest1,* 1Mathematics Institute, St Andrews University, St Andrews KY16 9SS, UK *Invited contribution by Eric Priest, recipient of the EGU Hannes Alfvén Medal for Scientists 2017 Correspondence to: Eric Priest ([email protected]) Received: 15 May 2017 – Accepted: 12 June 2017 – Published: 14 July 2017 Abstract. This lecture summarises how our understanding 1 Introduction of many aspects of the Sun has been revolutionised over the past few years by new observations and models. Much of the Thank you most warmly for the award of the Alfvén Medal, dynamic behaviour of the Sun is driven by the magnetic field which gives me great pleasure. In addition to a feeling of since, in the outer atmosphere, it represents the largest source surprise, I am also deeply humbled, because Alfvén was one of energy by far. of the greats in the field and one of my heroes as a young The interior of the Sun possesses a strong shear layer at the researcher (Fig. 1). We need dedicated scientists who fol- base of the convection zone, where sunspot magnetic fields low a specialised topic with tenacity and who complement are generated. A small-scale dynamo may also be operating one another in our amazingly diverse field; but we also need near the surface of the Sun, generating magnetic fields that time and space for creativity in this busy world, especially thread the lowest layer of the solar atmosphere, the turbulent for those princes of creativity, mavericks like Alfvén who can photosphere. -
Large-Scale Periodic Solar Velocities
LARGE-SCALE PERIODIC SOLAR VELOCITIES: AN OBSERVATIONAL STUDY (NASA-CR-153256) LARGE-SCALE PERIODIC SOLAR N77-26056 ElOCITIeS: AN OBSERVATIONAL STUDY Stanford Univ.) 211 p HC,A10/F A01 CSCL 03B Unclas G3/92 35416 by Phil Howard Dittmer Office of Naval Research Contract N00014-76-C-0207 National Aeronautics and Space Administration Grant NGR 05-020-559 National Science Foundation Grant ATM74-19007 Grant DES75-15664 and The Max C.Fleischmann Foundation SUIPR Report No. 686 T'A kj, JUN 1977 > March 1977 RECEIVED NASA STI FACILITY This document has been approved for public INPUT B N release and sale; its distribution isunlimited. 4 ,. INSTITUTE FOR PLASMA RESEARCH STANFORD UNIVERSITY, STANFORD, CALIFORNIA UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE (When Data Entered) DREAD INSTRUCTIONS REPORT DOCUMENTATION PAGE BEFORE COMPLETING FORM I- REPORT NUMBER 2 GOVT ACCESSION NO. 3. RECIPIENT'S CATALOG NUMBER SUIPR Report No. 686 4. TITLE (and Subtitle) 5 TYPE OF REPORT & PERIOD COVERED Large-Scale Periodic Solar Velocities: Scientific, Technical An Observational Study 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(s) 8 CONTRACT OR GRANT NUMBER(s) Phil Howard Dittmer N00014-76-C-0207 S PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT, PROJECT, TASK Institute for Plasma Research AREA & WORK UNIT NUMBERS Stanford University Stanford, California 94305 12. REPORT DATE . 13. NO. OF PAGES 11. CONTROLLING OFFICE NAME AND ADDRESS March 1977 211 Office of Naval Research Electronics Program Office 15. SECURITY CLASS. (of-this report) Arlington, Virginia 22217 Unclassified 14. MONITORING AGENCY NAME & ADDRESS (if diff. from Controlling Office) 15a. DECLASSIFICATION/DOWNGRADING SCHEDULE 16. DISTRIBUTION STATEMENT (of this report) This document has been approved for public release and sale; its distribution is unlimited. -
Solar and Space Physics: a Science for a Technological Society
Solar and Space Physics: A Science for a Technological Society The 2013-2022 Decadal Survey in Solar and Space Physics Space Studies Board ∙ Division on Engineering & Physical Sciences ∙ August 2012 From the interior of the Sun, to the upper atmosphere and near-space environment of Earth, and outwards to a region far beyond Pluto where the Sun’s influence wanes, advances during the past decade in space physics and solar physics have yielded spectacular insights into the phenomena that affect our home in space. This report, the final product of a study requested by NASA and the National Science Foundation, presents a prioritized program of basic and applied research for 2013-2022 that will advance scientific understanding of the Sun, Sun- Earth connections and the origins of “space weather,” and the Sun’s interactions with other bodies in the solar system. The report includes recommendations directed for action by the study sponsors and by other federal agencies—especially NOAA, which is responsible for the day-to-day (“operational”) forecast of space weather. Recent Progress: Significant Advances significant progress in understanding the origin from the Past Decade and evolution of the solar wind; striking advances The disciplines of solar and space physics have made in understanding of both explosive solar flares remarkable advances over the last decade—many and the coronal mass ejections that drive space of which have come from the implementation weather; new imaging methods that permit direct of the program recommended in 2003 Solar observations of the space weather-driven changes and Space Physics Decadal Survey. For example, in the particles and magnetic fields surrounding enabled by advances in scientific understanding Earth; new understanding of the ways that space as well as fruitful interagency partnerships, the storms are fueled by oxygen originating from capabilities of models that predict space weather Earth’s own atmosphere; and the surprising impacts on Earth have made rapid gains over discovery that conditions in near-Earth space the past decade. -
Solar Chromospheric Flares
Solar Chromospheric Flares A proposal for an ISSI International Team Lyndsay Fletcher (Glasgow) and Jana Kasparova (Ondrejov) Summary Solar flares are the most energetic energy release events in the solar system. The majority of energy radiated from a flare is produced in the solar chromosphere, the dynamic interface between the Sun’s photosphere and corona. Despite solar flare radiation having been known for decades to be principally chromospheric in origin, the attention of the community has re- cently been strongly focused on the corona. Progress in understanding chromospheric flare physics and the diagnostic potential of chromospheric observations has stagnated accord- ingly. But simultaneously, motivated by the available chromospheric observations, the ‘stan- dard flare model’, of energy transport by an electron beam from the corona, is coming under scrutiny. With this team we propose to return to the chromosphere for basic understanding. The present confluence of high quality chromospheric flare observations and sophisticated numerical simulation techniques, as well as the prospect of a new generation of missions and telescopes focused on the chromosphere, makes it an excellent time for this endeavour. The international team of experts in the theory and observation of solar chromospheric flares will focus on the question of energy deposition in solar flares. How can multi-wavelength, high spatial, spectral and temporal resolution observations of the flare chromosphere from space- and ground-based observatories be interpreted in the context of detailed modeling of flare radiative transfer and hydrodynamics? With these tools we can pin down the depth in the chromosphere at which flare energy is deposited, its time evolution and the response of the chromosphere to this dramatic event. -
Manual Ls40tha H-Alpha Solar-Telescope
Manual LS40THa H-alpha Solar-Telescope Telescope for solar observation in the H-Alpha wavelength. The H-alpha wavelength is the most impressive way to observe the sun, here prominences at the solar edge become visible, filaments and flares on the surface, and much more. Included Contents: - LS40THa telescope - H-alpha unit with tilt-tuning - Blocking-filter B500, B600, or B1200 - 1.25 inch Helical focuser - Dovetail bar (GP level) for installing at astronomical mounts - 1/4-20 tapped base (standard thread for photo-tripods) inside the dovetail for installing at photo-tripods - Sol-searcher Please note: Please keep the foam insert from the delivery box. The optionally available transport-case for the LS40THa (item number 0554010) is not supplied without such a foam insert, the original foam insert from the delivery box fits exactly into this transport-case. Congratulations and thank you for purchasing the LS40THa telescope from Lunt Solar Systems! The easy handling makes this telescope ideal for starting H-Alpha solar observation. Due to its compact dimensions it is also a good travel telescope for the experienced solar observers. Safety Information: There are inherent dangers when looking at the Sun thru any instrument. Lunt Solar Systems has taken your safety very seriously in the design of our systems. With safety being the highest priority we ask that you read and understand the operation of your telescope or filter system prior to use. Never attempt to disassemble the telescope! Do not use your system if it is in someway compromised due to mishandling or damage. Please contact our customer service with any questions or concerns regarding the safe use of your instrument. -
Formation and Evolution of Coronal Rain Observed by SDO/AIA on February 22, 2012?
A&A 577, A136 (2015) Astronomy DOI: 10.1051/0004-6361/201424101 & c ESO 2015 Astrophysics Formation and evolution of coronal rain observed by SDO/AIA on February 22, 2012? Z. Vashalomidze1;2, V. Kukhianidze2, T. V. Zaqarashvili1;2, R. Oliver3, B. Shergelashvili1;2, G. Ramishvili2, S. Poedts4, and P. De Causmaecker5 1 Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria e-mail: [teimuraz.zaqarashvili]@oeaw.ac.at 2 Abastumani Astrophysical Observatory at Ilia State University, Cholokashvili Ave.3/5, Tbilisi, Georgia 3 Departament de Física, Universitat de les Illes Balears, 07122, Palma de Mallorca, Spain 4 Dept. of Mathematics, Centre for Mathematical Plasma Astrophysics, Celestijnenlaan 200B, 3001 Leuven, Belgium 5 Dept. of Computer Science, CODeS & iMinds-iTEC, KU Leuven, KULAK, E. Sabbelaan 53, 8500 Kortrijk, Belgium Received 30 April 2014 / Accepted 25 March 2015 ABSTRACT Context. The formation and dynamics of coronal rain are currently not fully understood. Coronal rain is the fall of cool and dense blobs formed by thermal instability in the solar corona towards the solar surface with acceleration smaller than gravitational free fall. Aims. We aim to study the observational evidence of the formation of coronal rain and to trace the detailed dynamics of individual blobs. Methods. We used time series of the 171 Å and 304 Å spectral lines obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO) above active region AR 11420 on February 22, 2012. Results. Observations show that a coronal loop disappeared in the 171 Å channel and appeared in the 304 Å line more than one hour later, which indicates a rapid cooling of the coronal loop from 1 MK to 0.05 MK. -
Why Is the Corona Hotter Than It Has Any Right to Be?
Why is the corona hotter than it has any right to be? Sam Van Kooten CU Boulder SHINE 2019 Student Day Thanks to Steve Cranmer for some slides Why the Sun is the way it is The Sun is magnetically active The Sun rotates differentially Rotation + plasma = magnetism Magnetism + rotation = solar activity That’s why the Sun is the way it is Temperature Profile of the Solar Atmosphere Photosphere (top of the convection zone) Chromosphere (forest of complex structures) Corona (magnetic domination & heating conundrum) Coronal Heating ● How do you achieve those temperatures? ● Step 1: Have energy ● Step 2: Move energy ● Step 3: Turn energy to heat ● Step 4: Retain heat ● Step 5: HOT Step 1: Have energy ● The photosphere’s kinetic energy is enough by orders of magnitude Photospheric granulation Photospheric granulation Step 2: Move energy “DC” field-line braiding → “nanoflares” “AC” MHD waves “Taylor relaxation” “IR” (twist wants to untwist, due to mag. tension) Step 3: Turn energy to heat ● Turbulence ¯\_( )_/¯ ツ Step 4: Retain heat ● Very hot → complete ionization → no blackbody radiation → very limited cooling ● Combined with low density, required heat isn’t too mind-boggling Step 5: HOT So what’s the “coronal heating problem”? Cranmer & Winebarger (2019) So what’s the “coronal heating problem”? ● The theory side is fine ● All coronal heating models occur at small scales in thin plasmas – Really hard to see! ● It’s an observational problem – Can’t observe heating happening – Can’t measure or rule out models So why is the corona hotter than it -
Multi-Spacecraft Analysis of the Solar Coronal Plasma
Multi-spacecraft analysis of the solar coronal plasma Von der Fakultät für Elektrotechnik, Informationstechnik, Physik der Technischen Universität Carolo-Wilhelmina zu Braunschweig zur Erlangung des Grades einer Doktorin der Naturwissenschaften (Dr. rer. nat.) genehmigte Dissertation von Iulia Ana Maria Chifu aus Bukarest, Rumänien eingereicht am: 11.02.2015 Disputation am: 07.05.2015 1. Referent: Prof. Dr. Sami K. Solanki 2. Referent: Prof. Dr. Karl-Heinz Glassmeier Druckjahr: 2016 Bibliografische Information der Deutschen Nationalbibliothek Die Deutsche Nationalbibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie; detaillierte bibliografische Daten sind im Internet über http://dnb.d-nb.de abrufbar. Dissertation an der Technischen Universität Braunschweig, Fakultät für Elektrotechnik, Informationstechnik, Physik ISBN uni-edition GmbH 2016 http://www.uni-edition.de © Iulia Ana Maria Chifu This work is distributed under a Creative Commons Attribution 3.0 License Printed in Germany Vorveröffentlichung der Dissertation Teilergebnisse aus dieser Arbeit wurden mit Genehmigung der Fakultät für Elektrotech- nik, Informationstechnik, Physik, vertreten durch den Mentor der Arbeit, in folgenden Beiträgen vorab veröffentlicht: Publikationen • Mierla, M., Chifu, I., Inhester, B., Rodriguez, L., Zhukov, A., 2011, Low polarised emission from the core of coronal mass ejections, Astronomy and Astrophysics, 530, L1 • Chifu, I., Inhester, B., Mierla, M., Chifu, V., Wiegelmann, T., 2012, First 4D Recon- struction of an Eruptive Prominence -
Three-Dimensional Convective Velocity Fields in the Solar Photosphere
Three-dimensional convective velocity fields in the solar photosphere 太陽光球大気における3次元対流速度場 Takayoshi OBA Doctor of Philosophy Department of Space and Astronautical Science, School of Physical sciences, SOKENDAI (The Graduate University for Advanced Studies) submitted 2018 January 10 3 Abstract The solar photosphere is well-defined as the solar surface layer, covered by enormous number of bright rice-grain-like spot called granule and the surrounding dark lane called intergranular lane, which is a visible manifestation of convection. A simple scenario of the granulation is as follows. Hot gas parcel rises to the surface owing to an upward buoyant force and forms a bright granule. The parcel decreases its temperature through the radiation emitted to the space and its density increases to satisfy the pressure balance with the surrounding. The resulting negative buoyant force works on the parcel to return back into the subsurface, forming a dark intergranular lane. The enormous amount of the kinetic energy deposited in the granulation is responsible for various kinds of astrophysical phenomena, e.g., heating the outer atmospheres (the chromosphere and the corona). To disentangle such granulation-driven phenomena, an essential step is to understand the three-dimensional convective structure by improving our current understanding, such as the above-mentioned simple scenario. Unfortunately, our current observational access is severely limited and is far from that objective, leaving open questions related to vertical and horizontal flows in the granula- tion, respectively. The first issue is several discrepancies in the vertical flows derived from the observation and numerical simulation. Past observational studies reported a typical magnitude relation, e.g., stronger upflow and weaker downflow, with typical amplitude of ≈ 1 km/s. -
What Causes the High Apparent Speeds in Chromospheric and Transition Region Spicules on the Sun?
The Astrophysical Journal Letters, 849:L7 (7pp), 2017 November 1 https://doi.org/10.3847/2041-8213/aa9272 © 2017. The American Astronomical Society. All rights reserved. What Causes the High Apparent Speeds in Chromospheric and Transition Region Spicules on the Sun? Bart De Pontieu1,2 , Juan Martínez-Sykora1,3 , and Georgios Chintzoglou1,4 1 Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA 94304, USA; [email protected] 2 Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo, Norway 3 Bay Area Environmental Research Institute, Petaluma, CA 94952, USA 4 University Corporation for Atmospheric Research, Boulder, CO 80307-3000, USA Received 2017 June 22; revised 2017 October 5; accepted 2017 October 9; published 2017 October 23 Abstract Spicules are the most ubuiquitous type of jets in the solar atmosphere. The advent of high-resolution imaging and spectroscopy from the Interface Region Imaging Spectrograph (IRIS) and ground-based observatories has revealed the presence of very high apparent motions of order 100–300 km s−1 in spicules, as measured in the plane of the sky. However, line of sight measurements of such high speeds have been difficult to obtain, with values deduced from Doppler shifts in spectral lines typically of order 30–70 km s−1. In this work, we resolve this long-standing discrepancy using recent 2.5D radiative MHD simulations. This simulation has revealed a novel driving mechanism for spicules in which ambipolar diffusion resulting from ion-neutral interactions plays a key role. In our simulation, we often see that the upward propagation of magnetic waves and electrical currents from the low chromosphere into already existing spicules can lead to rapid heating when the currents are rapidly dissipated by ambipolar diffusion. -
The Sun's Dynamic Atmosphere
Lecture 16 The Sun’s Dynamic Atmosphere Jiong Qiu, MSU Physics Department Guiding Questions 1. What is the temperature and density structure of the Sun’s atmosphere? Does the atmosphere cool off farther away from the Sun’s center? 2. What intrinsic properties of the Sun are reflected in the photospheric observations of limb darkening and granulation? 3. What are major observational signatures in the dynamic chromosphere? 4. What might cause the heating of the upper atmosphere? Can Sound waves heat the upper atmosphere of the Sun? 5. Where does the solar wind come from? 15.1 Introduction The Sun’s atmosphere is composed of three major layers, the photosphere, chromosphere, and corona. The different layers have different temperatures, densities, and distinctive features, and are observed at different wavelengths. Structure of the Sun 15.2 Photosphere The photosphere is the thin (~500 km) bottom layer in the Sun’s atmosphere, where the atmosphere is optically thin, so that photons make their way out and travel unimpeded. Ex.1: the mean free path of photons in the photosphere and the radiative zone. The photosphere is seen in visible light continuum (so- called white light). Observable features on the photosphere include: • Limb darkening: from the disk center to the limb, the brightness fades. • Sun spots: dark areas of magnetic field concentration in low-mid latitudes. • Granulation: convection cells appearing as light patches divided by dark boundaries. Q: does the full moon exhibit limb darkening? Limb Darkening: limb darkening phenomenon indicates that temperature decreases with altitude in the photosphere. Modeling the limb darkening profile tells us the structure of the stellar atmosphere.