Download or read book Magnetic Origins of Cool Plasma in the Sun s Corona written by Emily Irene Mason and published by . This book was released on 2020 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: Much of solar physics research focuses on two questions: how the corona's temperature becomes hundreds of times hotter than the surface, and how the slow solar wind forms. Among the most fascinating phenomena produced by coronal heating is coronal rain, in which plasma undergoes rapid cooling (from roughly 106 to 103 K), condenses, and falls to the surface. One proposed rain origin theory, thermal nonequilibrium (TNE), posits a height restriction in coronal heating. By studying condensations, physicists hope to better understand coronal heating.Solar wind is often subdivided into fast and slow wind. The former originates in coronal hole regions; slow wind's source, however, is still under debate. One leading theory postulates that it comes from coronal hole boundaries, where magnetic field lines frequently reconnect.This dissertation investigates the origins and dynamics of coronal rain via study of recently-discovered structures called raining null-point topologies, or RNPTs. RNPTs - the first identification and characterization of which comprise part of this work - are decaying active regions situated near coronal hole boundaries, between 50-150 Mm in height. They are host to long periods of continuous coronal rain formation, and provide insight into coronal heating, slow solar wind origins, and coronal dynamics. This dissertation poses the following science questions:1. What specific mechanisms power the coronal rain and dynamics in RNPTs?2. What do these structures and the rain they contain tell us about the fundamental mechanisms of coronal heating?3. What do these structures and the rain they contain tell us about the fundamental origins and mechanisms of the slow solar wind?First, we focus on identifying and analyzing RNPTs' observational characteristics. We process and analyze RNPT data using both the Solar Dynamics Observatory Atmospheric Imaging Assembly and the Helioseismic and Magnetic Imager. Potential field source-surface extrapolations that model the magnetic field in the corona aid in the interpretation of the structures' topology. Next, we conduct a heating regime parameter study of 1D hydrodynamic simulations using the HYDrodynamic and RADiation Code (HYDRAD). This models a single flux tube that approaches the null, producing large asymmetry and a drastic cross-sectional expansion near the loop apex.Results indicate that RNPTs experience two rain-forming mechanisms, thermal nonequilibrium and interchange reconnection. The interchange reconnection is posited to power much of the early bursts of coronal rain, which constitutes a new rain-formation mechanism and allows for plasma from closed loops to escape into the slow solar wind. Observations also show evidence of partial condensations, which condense but do not fully cool. The results of the modeling study imply that heating scale heights in RNPTs must be much lower than in symmetric loops in order to support the observed TNE cycles. They also show that the apex's large expansion introduces a reverse siphon flow and suppresses condensations. The simulations show significant decreases in density near the apex and warm condensations, in good agreement with the observations. This two- pronged approach produces a broad yet detailed study of RNPT dynamics.
Download or read book Solar and Space Physics written by National Research Council and published by National Academies Press. This book was released on 2014-09-25 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 2010, NASA and the National Science Foundation asked the National Research Council to assemble a committee of experts to develop an integrated national strategy that would guide agency investments in solar and space physics for the years 2013-2022. That strategy, the result of nearly 2 years of effort by the survey committee, which worked with more than 100 scientists and engineers on eight supporting study panels, is presented in the 2013 publication, Solar and Space Physics: A Science for a Technological Society. This booklet, designed to be accessible to a broader audience of policymakers and the interested public, summarizes the content of that report.
Download or read book The Origin and Dynamics of Solar Magnetism written by M.J. Thompson and published by Springer Science & Business Media. This book was released on 2009-05-01 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Starting in 1995 numerical modeling of the Earth’s dynamo has ourished with remarkable success. Direct numerical simulation of convection-driven MHD- ow in a rotating spherical shell show magnetic elds that resemble the geomagnetic eld in many respects: they are dominated by the axial dipole of approximately the right strength, they show spatial power spectra similar to that of Earth, and the magnetic eld morphology and the temporal var- tion of the eld resembles that of the geomagnetic eld (Christensen and Wicht 2007). Some models show stochastic dipole reversals whose details agree with what has been inferred from paleomagnetic data (Glatzmaier and Roberts 1995; Kutzner and Christensen 2002; Wicht 2005). While these models represent direct numerical simulations of the fundamental MHD equations without parameterized induction effects, they do not match actual pla- tary conditions in a number of respects. Speci cally, they rotate too slowly, are much less turbulent, and use a viscosity and thermal diffusivity that is far too large in comparison to magnetic diffusivity. Because of these discrepancies, the success of geodynamo models may seem surprising. In order to better understand the extent to which the models are applicable to planetary dynamos, scaling laws that relate basic properties of the dynamo to the fundamental control parameters play an important role. In recent years rst attempts have been made to derive such scaling laws from a set of numerical simulations that span the accessible parameter space (Christensen and Tilgner 2004; Christensen and Aubert 2006).
Download or read book The Solar Corona written by Leon Golub and published by Cambridge University Press. This book was released on 2010 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Second edition graduate level textbook giving an up-to-date treatment of our understanding of the solar corona.
Download or read book Magnetohydrodynamics of the Sun written by Eric Priest and published by Cambridge University Press. This book was released on 2014-04-07 with total page 581 pages. Available in PDF, EPUB and Kindle. Book excerpt: This advanced textbook reviews the complex interaction between the Sun's plasma atmosphere and its magnetic field.
Download or read book Physics of the Solar Corona written by Constantin J. Macris and published by . This book was released on 1971 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Origin of Nonradiative Heating momentum in Hot Stars written by Anne Barbara Underhill and published by . This book was released on 1985 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sun Earth Plasma Connections written by James L. Burch and published by American Geophysical Union. This book was released on 1999-01-26 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 109. The Sun and the terrestrial magnetosphere have been the subjects of active research since the dawn of the space age. The capabilities of observing both systems with greater and greater detail evolved separately until the 1980s, when it was realized that definitive results on the connection between the Earth and the Sun would require a concerted and joint effort. It was also realized that sophisticated solar-terrestrial research communities existed within all the space-faring nations of the world and that no one of them could launch such an effort by itself. This realization led to the creation of the International Solar-Terrestrial Physics (ISTP) program, which now comprises at least 12 spacecraft and includes extensive ground-based observations and theory and modeling efforts.
Download or read book Physics of the Solar Corona written by C.J. Macris and published by Springer. This book was released on 1971-12-31 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Institute on Physics of the Solar Corona, held in Cavouri-Vouliagmeni, Athens, Greece, 6-17 September 1970
Download or read book Solar Energetic Particles written by Donald V. Reames and published by Springer. This book was released on 2017-03-10 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: This concise primer introduces the non-specialist reader to the physics of solar energetic particles (SEP) and systematically reviews the evidence for the two main mechanisms which lead to the so-called impulsive and gradual SEP events. More specifically, the timing of the onsets, the longitude distributions, the high-energy spectral shapes, the correlations with other solar phenomena (e.g. coronal mass ejections), as well as the all-important elemental and isotopic abundances of SEPs are investigated. Impulsive SEP events are related to magnetic reconnection in solar flares and jets. The concept of shock acceleration by scattering on self-amplified Alfvén waves is introduced, as is the evidence of reacceleration of impulsive-SEP material in the seed population accessed by the shocks in gradual events. The text then develops processes of transport of ions out to an observer. Finally, a new technique to determine the source plasma temperature in both impulsive and gradual events is demonstrated. Last but not least the role of SEP events as a radiation hazard in space is mentioned and a short discussion of the nature of the main particle telescope designs that have contributed to most of the SEP measurements is given.
Download or read book Physics of the Inner Heliosphere II written by Rainer Schwenn and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Physics of the Inner Heliosphere gives for the first time a comprehensive and complete summary of our knowledge of the inner solar system. Using data collected over more than 11 years by the HELIOS twin solar probes, one of the most successful ventures in unmanned space exploration, the authors have compiled six extensive reviews of the physical processes of the inner heliosphere and their relation to the solar atmosphere. Researchers and advanced students in space and plasma physics, astronomy, and solar physics will be surprised to see just how closely the heliosphere is tied to, and how sensitively it depends on, the sun. Volume 2 deals with particles, waves, and turbulence, with chapters on: - magnetic clouds - interplanetary clouds - the solar wind plasma and MHD turbulence - waves and instabilities - energetic particles in the inner solar system
Download or read book Plasma Properties and Magnetic Field Structure of the Solar Corona Based on Coordinated Max 1991 Observations from Serts the Vla and Magnetographs written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-09 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purposes of this investigation are to use existing, calibrated, coaligned sets of coordinated multiwaveband observations of the Sun to determine the coronal magnetic field strength and structure, and interpret the collective observations in terms of a self-consistent model of the coronal plasma and magnetic field. This information is vital to understanding processes such as coronal heating, solar wind acceleration, pre-flare energy storage, and active region evolution. Understanding these processes is the central theme of Max '91, the NASA-supported series of solar observing campaigns under which the observations acquired for this work were obtained. The observations came from NASA/GSFC's Solar EUV Rocket Telescope and Spectrograph (SERTS), the Very Large Array (VLA), and magnetographs. The technique of calculating the coronal magnetic field is to establish the contributions to the microwave emission from the two main emission mechanisms: thermal bremsstrahlung and thermal gyroemission. This is done by using the EUV emission to determine values of the coronal plasma quantities needed to calculate the thermal bremsstrahlung contribution to the microwave emission. Once the microwave emission mechanism(s) are determined, the coronal magnetic field can be calculated. A comparison of the coronal magnetic field derived from the coordinated multiwaveband observations with extrapolations from photospheric magnetograms will provide insight into the nature of the coronal magnetic field. Brosius, Jeffrey W. Unspecified Center NASW-4933...
Download or read book Los Alamos Science written by and published by . This book was released on 1980 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Space Weather and Coronal Mass Ejections written by Tim Howard and published by Springer Science & Business Media. This book was released on 2013-08-28 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: Space weather has attracted a lot of attention in recent times. Severe space weather can disrupt spacecraft, and on Earth can be the cause of power outages and power station failure. It also presents a radiation hazard for airline passengers and astronauts. These “magnetic storms” are most commonly caused by coronal mass ejections, or CMES, which are large eruptions of plasma and magnetic field from the Sun that can reach speeds of several thousand km/s. In this SpringerBrief, Space Weather and Coronal Mass Ejections, author Timothy Howard briefly introduces the coronal mass ejection, its scientific importance, and its relevance to space weather at Earth and other planets. This title focuses on the latest advances in CME observation and modeling, including new results from the NASA STEREO and SDO missions. It also includes topical issues regarding space weather and the most recent observations and anecdotal examples of the impacts of space weather and CMEs.
Download or read book Solar Terrestrial Physics 1970 written by International Symposium on Solar-Terrestial Physic and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 937 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the review papers presented at the International Symposium on Solar-Terrestrial Physics held at the Tavrichesky Palace, Leningrad, U.S.S.R., 11-19 May 1970. The Symposium may be regarded as the most recent member of a series of inter national symposia - for instance, the Symposium on Solar-Terrestrial Physics, Belgrade (1966), the Joint IQSY-COSPAR Symposium on Solar-Terrestrial Physics, London (1967), and the Symposium on the Physics of the Magnetosphere, Washington (1968). Like those earlier symposia, the Leningrad Symposium was sponsored by the International Astronomical Union (IAU), the International Union of Geodesy and Geophysics (IUGG), the International Union of Radio Sciences (URSI), and the ICSU Committee on Space Research (COSPAR). These bodies are all concerned with one or another aspect of solar-terrestrial physics, and all joined in believing that the time was ripe for another comprehensive symposium on all aspects of this very active field of research.
Download or read book MHD Waves in the Solar Atmosphere written by Bernard Roberts and published by Cambridge University Press. This book was released on 2019-07-18 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents a full mathematical exposition of the growing field of coronal seismology which will prove invaluable for graduate students and researchers alike. Roberts' detailed and original research draws upon the principles of fluid mechanics and electromagnetism, as well as observations from the TRACE and SDO spacecraft and key results in solar wave theory. The unique challenges posed by the extreme conditions of the Sun's atmosphere, which often frustrate attempts to develop a comprehensive theory, are tackled with rigour and precision; complex models of sunspots, coronal loops and prominences are presented, based on a magnetohydrodynamic (MHD) view of the solar atmosphere, and making use of Faraday's concept of magnetic flux tubes to analyse oscillatory phenomena. The rapid rate of progress in coronal seismology makes this essential reading for those hoping to gain a deeper understanding of the field.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1993 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
