DOCSLIB.ORG

太空|TAIKONG 国际空间科学研究所 - 北京 ISSI-BJ Magazine No

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
太空|TAIKONG 国际空间科学研究所 - 北京 ISSI-BJ Magazine No 太空|TAIKONG 国际空间科学研究所 - 北京 ISSI-BJ Magazine No. 19 May 2020 IMPRINT FOREWORD 太空 | TAIKONG There is little doubt that today's political they undoubtedly play in how this system ISSI-BJ Magazine and business leaders, as well as society works and how it can be monitored. License: CC BY-NC-ND 4.0 at large, must face seriously the reality of global climate change and, in a broader This is not to say that these interactions perspective, define appropriate actions have not received their due attention. to protect our fragile high-technology They have. The vigorous and robust Address: No.1 Nanertiao, society against the broad spectrum research in Space Weather, which is Zhongguancun, of natural and anthropogenic hazards centered on these interactions, is one of Haidian District, which threatens it. There is an equal the highlights of Earth System Science in Beijing, China need for the scientific community to our still-young century. It is the interplay Postcode: 100190 and interaction of the Space Weather Phone: +86-10-62582811 offer an adequate response to this Website: www.issibj.ac.cn major scientific challenge and strive System with the theatre of Global together at the international level to Change, namely the troposphere, offer the science-based information oceans, land, and different life forms needed for society to take meaningful occupying the surface of Earth, which Authors actions. The fact that our science we believe have attracted insufficient sometimes still fails to give consistent, attention: these interactions are likely See the list on the back cover robust, and first-principle predictions actors in the underlying mechanisms of the occurrence and prediction of controlling natural hazards and Global these hazards is obviously related to Change in the same way as Global Editor the enormous complexity of the Earth Change and natural hazards originating System and to the long timescales from weather, lithospheric, and oceanic Laura Baldis, on which these predictions are to be processes and geomagnetic field International Space Science variations impact Space Weather. Institute - Beijing, China made. It is essential in this context to recognize our own shortcomings, i.e. Establishing a quantitative estimate of that we have not yet fully studied the these effects and of the associated energy Earth System as an interconnected transfer mechanisms, in both directions, whole. Future progress in this direction will be a major scientific breakthrough requires true multidisciplinary research, with profound implications. across a spectrum much wider than what a scientist is accustomed to today. This The central objective of the Forum on FRONT Forum addresses an important gap in the “Science Objectives and Observation COVER current global description of the Earth System for the International Meridian system: electrical, electromagnetic, and Circle”, whose scientific debates are summarized in this issue of Taikong The Earth magnetic field and magnetized plasma interactions in the its interaction with the Sun Earth System and the important roles Magazine, was to address this important Image Credit: Pixabay 2 太空|TAIKONG gap in the current description of the Earth hazards and serve the emergence of a new System and to offer directions to cover the understanding of our home planet. climate/weather system and space weather in a unified scientific perspective. Jointly organized We wish to thank the conveners and organizers by the International Meridian Circle Project of the Forum, as well as the ISSI-BJ staff, Lijuan at NSSC, CAS and the International Space En and Laura Baldis, for actively and cheerfully Science Institute - Beijing (ISSI-BJ), this forum supporting the organization of the Forum. We was successfully held in the premises of ISSI- would also like to thank all the participants BJ on September 23-25, 2019. It was convened who actively contributed to the Forum and by William Liu (NSSC, CAS, China), Michel to the editing of this report with dedication, Blanc (NSSC, CAS, China and IRAP, France), enthusiasm, and scientific rigor. Our special Eric Donovan (University of Calgary, Canada), thanks also go to Prof. Mioara Mandea and John Foster (MIT Haystack Observatory, Prof. Alain Hauchecorne for their precious USA), Mark Lester (Leicester University, UK), contributions to this report. Mioara Mandea (CNES, France) and Maurizio Falanga (ISSI-BJ, China), with the participation . of 34 scientific experts from 13 countries. Our primary goal was to take stock of our research Maurizio Falanga, legacy and arsenals in the Space Weather discipline and apply them to the detection and possible prediction of major natural and Executive Director anthropogenic hazards. This can be done by ISSI-BJ, China means of the deployment of a global natural screen on which these hazards can be projected and detected: our Ionosphere, Middle and William Liu, Upper Atmosphere (IMUA). The international team of participants undertook rigorous and enlightening discussions on future steps to meet this major scientific challenge by joining forces across the five continents. We hope that the summary of this forum will serve as a trigger NSSC, CAS, China for a soon-to-come broader international discussion in view of the deployment of the global ground-based observation system of the Michel Blanc, IMUA we are proposing. With the additional support of new space assets and state-of-the- art computation and modeling capabilities, we trust this IMCP observation system will provide an unprecedented global monitoring of natural NSSC, CAS, China IRAP, France 太空|TAIKONG 3 1. INTRODUCTION Our Spaceship Earth sails the Solar System Section 2 first establishes the “science case” in a sea of plasmas, interfacing with it via a for the IMCP. We summarize there how the critical boundary layer through which a broad different types of natural and anthropogenic diversity of energy transfer processes takes hazards, from solar and interplanetary place at time scales from a fraction of a second disturbances (disturbances “from above”) to millennia: our Earth’s Ionosphere, Upper, to Earthquakes, tropospheric weather and Middle Atmosphere, which will here be disturbances, greenhouse gases emissions named the IMUA for short. Understanding and long-term geomagnetic field variations the role that transfer processes through and (disturbances “from below”) affect the IMUA to the IMUA play in the global changes driven and produce imprints on it that can be used by natural and anthropogenic forcing affecting to monitor them. On the basis of this analysis, our planet is a major scientific challenge for we conclude by defining the “ideal” spatial the scientific community of the XXIst century. and temporal coverage required for the IMCP It is this challenge, and the grand vision of a observation system: a pair of two great meridian more comprehensive, better integrated and circles in quadrature covering all geographic truly interdisciplinary description of our Earth and geomagnetic latitudes and capturing the System, which the International Meridian Circle land-oceans contrast. Program (IMCP) has undertaken to meet. Starting from this scientific requirement, section The International Meridian Circle Program 3 describes how the two great meridians (IMCP) is an active proposal to the Chinese should be equipped with a set of instruments Ministry of Science and Technology for the that will provide a continuous survey of key international scientific community to address parameters of the IMUA. We first describe the this major scientific challenge. Building on categories of instruments that are needed as the already funded Chinese Meridian Project, global networks. We then focus on the design its ambition is to deploy and operate for the of the meridional chain of instruments running first time a global, internationally coordinated along the “primary” great circle (120° E and 60° observing system which will give us the W longitudes) which will link Eastern Siberia, capacity of monitoring at all relevant spatial Eastern Asia, Oceania, and the Americas with and temporal scales the diversity of energy one single and coherent observation system. transfer processes affecting the IMUA, may This primary instrument chain can largely be they be driven from above (interplanetary extrapolated from the instrument suite of the space) or from below (solid and fluid Earth). The Chinese Meridian Project (CMP), which we will main purpose of this report is to describe the describe first. We then study, with the precious successive scientific and logical steps leading contributions of the European and African to the design of such an observation system. experts present at the forum, the potential 4 太空|TAIKONG for the deployment of a second meridian needed in the definition of the IMCP scientific circle along the 30 E and 150 W longitudes, in analysis strategy to maximize its scientific quadrature with the first one, which will cover return. Europe, Africa and the Pacific. This second circle will significantly improve the spatial We conclude by drawing some perspectives for coverage of the IMCP while bringing new the future steps in the design and worldwide capabilities and new players into the project. deployment and operation of the IMCP with emphasis on the unique strength that a well- Section 4 offers a preliminary exploration of designed, balanced and global international the most advanced modelling, Big Data, and cooperation will empower into the project. The Artificial Intelligence tools, available today as need
Load more

Recommended publications
  • A Multislit Photoelectric Star Micrometer for the Meridian Circle of the Nikolayev Astronomical Observatory
    A Multislit Photoelectric Star Micrometer for the Meridian Circle of the Nikolayev Astronomical Observatory. V. V. Konin and A. D. Pogonij Nikolaev Astronomical Observatory, Nikolaev, USSR In the course of the cooperation between the Nikolaev and the Pulkovo Observatories, a photoelectric micrometer, similar to that proposed by E. Htfg, was designed and installed on the Repsold meridian circle. The optics of the finder includes an achromatic wedge for the deflection of light from the objective to the finderTs eyepiece. The grating is composed only of a system of inclined slits (Hrfg 1970, p. 92, No. 2). The slits are 5V3 wide and spaced at 38V3. One can use from 7 to 14 slit pairs in the micrometer for observations. A rectangular diaphragm isolates an element of 19" x 27" from the working grating. This has 4 initial positions. The required initial position depends on the instrument's position, the type of culmination and the observing interval (30s or 60s for an equatorial star). The diaphragm is moved by a stepping motor, whose speed of rotation is controlled by the observer and depends on declination. The motor can be switched on either by hand or automatically after the star appears in the field defined by the diaphragm. During transit, the clock readings of the start and the end of the observation are recorded with a precision of 0? 001. Photon counts are taken for every 0S1 time interval. There is a block for recording contact signals from a moving mark in the control unit (Konin et al., 1982). Karyakina et al.
    [Show full text]
  • Sun-Earth System Interaction Studies Over Vietnam: an International Cooperative Project
    Ann. Geophys., 24, 3313–3327, 2006 www.ann-geophys.net/24/3313/2006/ Annales © European Geosciences Union 2006 Geophysicae Sun-Earth System Interaction studies over Vietnam: an international cooperative project C. Amory-Mazaudier1, M. Le Huy2, Y. Cohen3, V. Doumbia4,*, A. Bourdillon5, R. Fleury6, B. Fontaine7, C. Ha Duyen2, A. Kobea4, P. Laroche8, P. Lassudrie-Duchesne6, H. Le Viet2, T. Le Truong2, H. Luu Viet2, M. Menvielle1, T. Nguyen Chien2, A. Nguyen Xuan2, F. Ouattara9, M. Petitdidier1, H. Pham Thi Thu2, T. Pham Xuan2, N. Philippon**, L. Tran Thi2, H. Vu Thien10, and P. Vila1 1CETP/CNRS, 4 Avenue de Neptune, 94107 Saint-Maur-des-Fosses,´ France 2Institute of Geophysics, Vietnamese Academy of Science and Technology , 18 Hoang Quoc Viet, Cau Giay, Hano¨ı, Vietnam 3IPGP, 4 Avenue de Neptune, 94107 Saint-Maur-des-Fosses,´ France 4Laboratoire de Physique de l’Atmosphere,` Universite´ d’Abidjan Cocody 22 B.P. 582, Abidjan 22, Coteˆ d’Ivoire 5Institut d’Electronique et de Tel´ ecommunications,´ Universite´ de Rennes Batˆ 11D, Campus Beaulieu, 35042 Rennes, cedex,´ France 6ENST, Universite´ de Bretagne Occidentale, CS 83818, 29288 Brest, cedex´ 3, France 7CRC , Faculte´ des Sciences, 6 Boulevard Gabriel, F 21004 Dijon cedex´ 04, France 8Unite´ de Recherche Environnement Atmospherique,´ ONERA, 92332 Chatillon, cedex,´ France 9University of Koudougou, Burkina Faso 10Laboratoire signaux et systemes,` CNAM, 292 Rue saint Martin, 75141 Paris cedex´ 03, France *V. Doumbia previously signed V. Doumouya **affiliation unknown Received: 15 June 2006 – Revised: 19 October 2006 – Accepted: 8 November 2006 – Published: 21 December 2006 Abstract. During many past decades, scientists from var- the E, F1 and F2 ionospheric layers follow the variation of ious countries have studied separately the atmospheric mo- the sunspot cycle.
    [Show full text]
  • The Oscillating Slit Micrometer of the Meridian Circle Pmc 190 Tokyo
    THE OSCILLATING SLIT MICROMETER OF THE MERIDIAN CIRCLE PMC 190 TOKYO C. Kuhne, Carl Zeiss, D-7082 Oberkochen, Federal Republic of Germany M. Miyamoto, M. Yoshizawa, Tokyo Astronomical Observatory, Mitaka, Tokyo 181, Japan ABSTRACT The meridian circle installed at the Tokyo Astronomical Observatory in 1982/83 is equipped with a photoelectric Double Slit Micrometer which is one of the basic prerequisites for fully automatic observation. A slit plate is located in the image field of the telescope. It oscil­ lates parallel to right ascension while being guided at the mean tra­ veling speed of the star. The paper describes the procedure by which the moment of the star pas­ sage through the instruments meridian and declination is determined. Furthermore, the autocollimation devices are described which are an essential prerequisite for the determination and periodical checking of the instrumental errors. Also, the measuring devices for the passage of the sun and the moon are dealt with briefly. 1 . INTRODUCTION The Double Slit Micrometer was introduced in 1972 by the first author during the engineering phase of the meridian circle project. The con­ cept is based on the multislit micrometer used by E. H<6g (1970) at the meridian circle in Perth. The +_ 45° inclination was retained, but the multitude of slits was replaced by only one movable pair. Therefore, the system became independent of the starfs velocity, a higher degree of statistic averaging could be applied, and a more simple and stable kind of collimation measurement became available. 2. DESIGN PRINCIPLE The telescope of the PMC 190 has a double-walled tube whose inner part houses the objective and the section of the micrometer which has to per- 379 H.
    [Show full text]
  • Chapter 7 Mapping The
    BASICS OF RADIO ASTRONOMY Chapter 7 Mapping the Sky Objectives: When you have completed this chapter, you will be able to describe the terrestrial coordinate system; define and describe the relationship among the terms com- monly used in the “horizon” coordinate system, the “equatorial” coordinate system, the “ecliptic” coordinate system, and the “galactic” coordinate system; and describe the difference between an azimuth-elevation antenna and hour angle-declination antenna. In order to explore the universe, coordinates must be developed to consistently identify the locations of the observer and of the objects being observed in the sky. Because space is observed from Earth, Earth’s coordinate system must be established before space can be mapped. Earth rotates on its axis daily and revolves around the sun annually. These two facts have greatly complicated the history of observing space. However, once known, accu- rate maps of Earth could be made using stars as reference points, since most of the stars’ angular movements in relationship to each other are not readily noticeable during a human lifetime. Although the stars do move with respect to each other, this movement is observable for only a few close stars, using instruments and techniques of great precision and sensitivity. Earth’s Coordinate System A great circle is an imaginary circle on the surface of a sphere whose center is at the center of the sphere. The equator is a great circle. Great circles that pass through both the north and south poles are called meridians, or lines of longitude. For any point on the surface of Earth a meridian can be defined.
    [Show full text]
  • Astrometry and Optics During the Past 2000 Years
    1 Astrometry and optics during the past 2000 years Erik Høg Niels Bohr Institute, Copenhagen, Denmark 2011.05.03: Collection of reports from November 2008 ABSTRACT: The satellite missions Hipparcos and Gaia by the European Space Agency will together bring a decrease of astrometric errors by a factor 10000, four orders of magnitude, more than was achieved during the preceding 500 years. This modern development of astrometry was at first obtained by photoelectric astrometry. An experiment with this technique in 1925 led to the Hipparcos satellite mission in the years 1989-93 as described in the following reports Nos. 1 and 10. The report No. 11 is about the subsequent period of space astrometry with CCDs in a scanning satellite. This period began in 1992 with my proposal of a mission called Roemer, which led to the Gaia mission due for launch in 2013. My contributions to the history of astrometry and optics are based on 50 years of work in the field of astrometry but the reports cover spans of time within the past 2000 years, e.g., 400 years of astrometry, 650 years of optics, and the “miraculous” approval of the Hipparcos satellite mission during a few months of 1980. 2011.05.03: Collection of reports from November 2008. The following contains overview with summary and link to the reports Nos. 1-9 from 2008 and Nos. 10-13 from 2011. The reports are collected in two big file, see details on p.8. CONTENTS of Nos. 1-9 from 2008 No. Title Overview with links to all reports 2 1 Bengt Strömgren and modern astrometry: 5 Development of photoelectric astrometry including the Hipparcos mission 1A Bengt Strömgren and modern astrometry ..
    [Show full text]
  • 212 Publications of the Some Pioneer
    212 PUBLICATIONS OF THE SOME PIONEER OBSERVERS1 By Frank Schlesinger In choosing a subject upon which to speak to you this eve- ning, I have had to bear in mind that, although this is a meeting of the Astronomical Society of the Pacific, not many of my audience are astronomers, and I am therefore debarred from speaking on too technical a matter. Under these circumstances I have thought that a historical subject, and one that has been somewhat neglected by the, formal historians of our science, may be of interest. I propose to outline, very briefly of course, the history of the advances that have been made in the accuracy of astronomical measurements. To do this within an hour, I must confine myself to the measurement of the relative places of objects not very close together, neglecting not only measure- ments other than of angles, but also such as can be carried out, for example, by the filar micrometer and the interferometer; these form a somewhat distinct chapter and would be well worth your consideration in an evening by themselves. It is clear to you, I hope, in how restricted a sense I am using the word observer ; Galileo, Herschel, and Barnard were great observers in another sense and they were great pioneers. But of their kind of observing I am not to speak to you tonight. My pioneers are five in number ; they are Hipparchus in the second century b.c., Tycho in the sixteenth century, Bradley in the eighteenth, Bessel in the first half of the nineteenth century and Rüther fur d in the second half.
    [Show full text]
  • Theory, Modeling, and Integrated Studies in the Arase (ERG) Project
    Seki et al. Earth, Planets and Space (2018) 70:17 https://doi.org/10.1186/s40623-018-0785-9 FULL PAPER Open Access Theory, modeling, and integrated studies in the Arase (ERG) project Kanako Seki1* , Yoshizumi Miyoshi2, Yusuke Ebihara3, Yuto Katoh4, Takanobu Amano1, Shinji Saito5, Masafumi Shoji2, Aoi Nakamizo6, Kunihiro Keika1, Tomoaki Hori2, Shin’ya Nakano7, Shigeto Watanabe8, Kei Kamiya5, Naoko Takahashi1, Yoshiharu Omura3, Masahito Nose9, Mei‑Ching Fok10, Takashi Tanaka11, Akimasa Ieda2 and Akimasa Yoshikawa11 Abstract Understanding of underlying mechanisms of drastic variations of the near-Earth space (geospace) is one of the current focuses of the magnetospheric physics. The science target of the geospace research project Exploration of energiza‑ tion and Radiation in Geospace (ERG) is to understand the geospace variations with a focus on the relativistic electron acceleration and loss processes. In order to achieve the goal, the ERG project consists of the three parts: the Arase (ERG) satellite, ground-based observations, and theory/modeling/integrated studies. The role of theory/modeling/integrated studies part is to promote relevant theoretical and simulation studies as well as integrated data analysis to combine diferent kinds of observations and modeling. Here we provide technical reports on simulation and empirical models related to the ERG project together with their roles in the integrated studies of dynamic geospace variations. The simu‑ lation and empirical models covered include the radial difusion model of the radiation belt electrons, GEMSIS-RB and RBW models, CIMI model with global MHD simulation REPPU, GEMSIS-RC model, plasmasphere thermosphere model, self-consistent wave–particle interaction simulations (electron hybrid code and ion hybrid code), the ionospheric electric potential (GEMSIS-POT) model, and SuperDARN electric feld models with data assimilation.
    [Show full text]
  • Selected Astrometric Catalogues
    1 Contribution to the history of astrometry No. 6 8 May 2016 Revision of the version of 25 November 2008, DRAFT including much new information on the catalogues before 1800 AD Selected astrometric catalogues Erik Høg, Niels Bohr Institute, Copenhagen, Denmark ABSTRACT: A selection of astrometric catalogues are presented in three tables for respectively positions, proper motions and trigonometric parallaxes. The tables contain characteristics of each catalogue showing the evolution in optical astrometry, in fact the evolution during the past 2000 years for positions. The number of stars and the accuracy are summarized by the weight of a catalogue, proportional with the number of stars and the statistical weight. The present report originally from 2008 was revised in 2016 with much new information about the accuracy of catalogues before 1800 AD. Introduction The 400 years of astrometry from Tycho Brahe to the Hipparcos mission have been reviewed (Høg 2008d) for the symposium held at ESTEC in September 2008 to celebrate the 400 years of astronomical telescopes. For this purpose the Tables 1 to 3 were elaborated, containing data for selected astrometric catalogues for positions, proper motions and trigonometric parallaxes, respectively. The tables give characteristics of each catalogue showing the evolution over the past 400 years in optical astrometry. The number of stars, N, and the accuracy, i.e. the standard error, s, are summarized by the weight of a catalogue, W, defined in all tables as W = N s -2 10 -6, proportional with the number of stars and the statistical weight. The table entries are documented in a separate paper (Høg 2016) where the origin of the new information on catalogues before 1800 AD is given.
    [Show full text]
  • A History of Star Catalogues
    A History of Star Catalogues © Rick Thurmond 2003 Abstract Throughout the history of astronomy there have been a large number of catalogues of stars. The different catalogues reflect different interests in the sky throughout history, as well as changes in technology. A star catalogue is a major undertaking, and likely needs strong justification as well as the latest instrumentation. In this paper I will describe a representative sample of star catalogues through history and try to explain the reasons for conducting them and the technology used. Along the way I explain some relevent terms in italicized sections. While the story of any one catalogue can be the subject of a whole book (and several are) it is interesting to survey the history and note the trends in star catalogues. 1 Contents Abstract 1 1. Origin of Star Names 4 2. Hipparchus 4 • Precession 4 3. Almagest 5 4. Ulugh Beg 6 5. Brahe and Kepler 8 6. Bayer 9 7. Hevelius 9 • Coordinate Systems 14 8. Flamsteed 15 • Mural Arc 17 9. Lacaille 18 10. Piazzi 18 11. Baily 19 12. Fundamental Catalogues 19 12.1. FK3-FK5 20 13. Berliner Durchmusterung 20 • Meridian Telescopes 21 13.1. Sudlich Durchmusterung 21 13.2. Cordoba Durchmusterung 22 13.3. Cape Photographic Durchmusterung 22 14. Carte du Ciel 23 2 15. Greenwich Catalogues 24 16. AGK 25 16.1. AGK3 26 17. Yale Bright Star Catalog 27 18. Preliminary General Catalogue 28 18.1. Albany Zone Catalogues 30 18.2. San Luis Catalogue 31 18.3. Albany Catalogue 33 19. Henry Draper Catalogue 33 19.1.
    [Show full text]
  • Locations of Chorus Emissions Observed by the Polar Plasma Wave Instrument K
    JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115, A00F12, doi:10.1029/2009JA014579, 2010 Click Here for Full Article Locations of chorus emissions observed by the Polar Plasma Wave Instrument K. Sigsbee,1 J. D. Menietti,1 O. Santolík,2,3 and J. S. Pickett1 Received 18 June 2009; revised 20 November 2009; accepted 17 December 2009; published 8 June 2010. [1] We performed a statistical study of the locations of chorus emissions observed by the Polar spacecraft’s Plasma Wave Instrument (PWI) from March 1996 to September 1997, near the minimum of solar cycles 22/23. We examined how the occurrence of chorus emissions in the Polar PWI data set depends upon magnetic local time, magnetic latitude, L shell, and L*. The Polar PWI observed chorus most often over a range of magnetic local times extending from about 2100 MLT around to the dawn flank and into the dayside magnetosphere near 1500 MLT. Chorus was least likely to be observed near the dusk flank. On the dayside, near noon, the region in which Polar observed chorus extended to larger radial distances and higher latitudes than at other local times. Away from noon, the regions in which chorus occurred were more restricted in both radial and latitudinal extent. We found that for high‐latitude chorus near local noon, L* provides a more reasonable mapping to the equatorial plane than the standard L shell. Chorus was observed slightly more often when the magnitude of the solar wind magnetic field BSW was greater than 5 nT than it was for smaller interplanetary magnetic field strengths.
    [Show full text]
  • The Near-Earth Plasma Environment
    Space Sci Rev (2012) 168:23–112 DOI 10.1007/s11214-012-9872-6 The Near-Earth Plasma Environment Robert F. Pfaff Jr. Received: 1 March 2012 / Accepted: 3 March 2012 / Published online: 20 June 2012 © US Government 2012 Abstract An overview of the plasma environment near the earth is provided. We describe how the near-earth plasma is formed, including photo-ionization from solar photons and impact ionization at high latitudes from energetic particles. We review the fundamental characteristics of the earth’s plasma environment, with emphasis on the ionosphere and its interactions with the extended neutral atmosphere. Important processes that control iono- spheric physics at low, middle, and high latitudes are discussed. The general dynamics and morphology of the ionized gas at mid- and low-latitudes are described including electro- dynamic contributions from wind-driven dynamos, tides, and planetary-scale waves. The unique properties of the near-earth plasma and its associated currents at high latitudes are shown to depend on precipitating auroral charged particles and strong electric fields which map earthward from the magnetosphere. The upper atmosphere is shown to have profound effects on the transfer of energy and momentum between the high-latitude plasma and the neutral constituents. The article concludes with a discussion of how the near-earth plasma responds to magnetic storms associated with solar disturbances. Keywords Ionosphere · Upper atmosphere · Electric fields 1 Introduction In this article we discuss the near-earth plasma environment, for which the ionosphere is the natural focus. Because this ionized gas co-exists with the neutral atmospheric gas to which it is coupled, the ionized/neutral gas system is more properly considered a partially ionized gas rather than a medium consisting of two distinct, independent fluids.
    [Show full text]
  • Celestial Sphere
    ASTR 111 – 003 Fall 2007 Lecture 02 Sep. 10, 2007 Introduction To Modern Astronomy I: Solar System Ch1: Astronomy and the Universe Introducing Astronomy (chap. 1-6) Ch2: Knowing the Heavens Ch3: Eclipses and the Motion of the Moon Planets and Moons (chap. 7-15) Ch4: Gravitation and the Waltz of the Planets Ch5: The Nature of Light Chap. 16: Our Sun Ch6: Optics and Telescope Chap. 28: Search for Extraterrestrial life Knowing the Heavens Chapter Two Hawaii: N20° Washington D.C.: N38° Positional Astronomy • Positional astronomy – the study of the positions of objects in the sky and how these positions change • It has roots in almost all ancient civilizations • Naked-eye astronomy – the sort that requires only human vision (no telescope) The Sun Dagger at Chaco Canyon, New Mexico Positional Astronomy • Position of stars in the heaven; forming consternations • Path of Sun, Moon and Planets; forming zodiac band Heaven’s Sphere at Purple Mountain Observatory, Nanjing, China Constellations From the Latin for “group of stars” ORION: Photograph Modern Star Atlas Ancient Star Atlas(1835) ORION (the Hunter) Betelgeuse: the armpit; Mintaka: the belt Constellations •Zodiac Constellations: 12 in total along the ecliptic path Constellations • On modern star charts, the entire sky is divided into 88 constellations • Starts in the same constellation only appear to be close, because they are in nearly the same direction as seen from Earth • However, most stars in a constellation are nowhere near one another in real 3-D distance. North Star: Polaris •Visible
    [Show full text]