Magnetohydrodynamic Shock Heating and Solar Wind Acceleration at Coronal Holes PDF Download
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Author: José Alejandro Orta Ortiz de Zárate
Publisher:
ISBN:
Category : Coronal holes (Astronomy)
Languages : en
Pages : 542
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Book Description
Author: José Alejandro Orta Ortiz de Zárate
Publisher:
ISBN:
Category : Coronal holes (Astronomy)
Languages : en
Pages : 542
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Book Description
Author: John L. Kohl
Publisher: Springer Science & Business Media
ISBN: 9401591679
Category : Science
Languages : en
Pages : 360
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Book Description
The SOHO-7 Workshop was held from 28 September through 1 October 1998 at the Asticou Inn in Northeast Harbor, Maine. The primary topic of this Workshop was the impact of SOHO observations on our understanding of the nature and evolution of coronal holes and the acceleration and composition of the solar wind. The presentations and discussions occasionally went beyond this topic to include the impact of the reported research on other solar structures and the heliosphere. SOHO (the Solar and Heliospheric Observatory), a project of international cooperation between ESA and NASA, was launched in December 1995 and began its science operations during the first few months of 1996. To many solar and space physicists, it was a great advantage that SOHO began itscomprehensive look at the Sun during the 1996 solar minimum. The qualitatively simple two-phase corona, with polar coronal holes expanding into the high-speed solar wind, and a steady equatorial streamer belt related somehow to the stochastic slow-speed solar wind, allowed various SOHO diagnostics to be initiated with a reasonably well understoodcircumsolar geometry. The analysis of subsequentSOHO measurements made during the rising phase of solar cycle 23 will continue to benefit from what has been learned from the first two years of data.
Author: Xueshang Feng
Publisher: Springer
ISBN: 9811390819
Category : Science
Languages : en
Pages : 772
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Book Description
The book covers intimately all the topics necessary for the development of a robust magnetohydrodynamic (MHD) code within the framework of the cell-centered finite volume method (FVM) and its applications in space weather study. First, it presents a brief review of existing MHD models in studying solar corona and the heliosphere. Then it introduces the cell-centered FVM in three-dimensional computational domain. Finally, the book presents some applications of FVM to the MHD codes on spherical coordinates in various research fields of space weather, focusing on the development of the 3D Solar-InterPlanetary space-time Conservation Element and Solution Element (SIP-CESE) MHD model and its applications to space weather studies in various aspects. The book is written for senior undergraduates, graduate students, lecturers, engineers and researchers in solar-terrestrial physics, space weather theory, modeling, and prediction, computational fluid dynamics, and MHD simulations. It helps readers to fully understand and implement a robust and versatile MHD code based on the cell-centered FVM.
Author: Markus Aschwanden
Publisher: Springer Science & Business Media
ISBN: 9783540307655
Category : Science
Languages : en
Pages : 946
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Book Description
A thorough introduction to solar physics based on recent spacecraft observations. The author introduces the solar corona and sets it in the context of basic plasma physics before moving on to discuss plasma instabilities and plasma heating processes. The latest results on coronal heating and radiation are presented. Spectacular phenomena such as solar flares and coronal mass ejections are described in detail, together with their potential effects on the Earth.
Author: Rebekah Minnel Evans Frolov
Publisher:
ISBN:
Category : Coronal mass ejections
Languages : en
Pages : 0
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Book Description
Coronal mass ejections (CMEs) and their associated shocks are major sources of space weather. In order to forecast their impact at Earth, it is crucial to accurately model their propagation in interplanetary space. The only tool capable of treating the large scales of CME evolution is global magnetohydrodynamics (MHD) modeling. However, this approach cannot resolve the small scales on which important processes occur (such as the acceleration of the solar wind and coronal heating). The solar wind solution depends on which method is utilized to mimic these processes. And because the evolution of a CME depends crucially on its interaction with the solar wind, the CME evolution will also be connected to the heating mechanisms and drivers utilized in an MHD model. In the first part of the thesis, we show that the ad hoc approaches to coronal heating used in global MHD models leads to unphysical conditions for CME-driven shock formation in the lower corona (1-10 solar radii). We present this argument in two steps. First, we present a CME simulation in which the solar wind was accelerated and heated by reducing the value of the polytropic index (to less than the adiabatic value) in the lower corona. As it is not well understood, we do not model the CME initiation process - we utilize an out-of-equilibrium Titov-Demoulin flux rope to begin the eruption. We analyze several aspects of the CME, such as its kinematics and energy evolution, the shock formation and evolution, the plasma flows in the CME-sheath and their connection to the CME magnetic field vector, and the plasma pile-up at the front of the CME. We find that some characteristics are inconsistent with the observed properties of CMEs, and we connect these to the ad hoc treatment of the solar wind heating. Second, we use data of CME shock-accelerated solar energetic particle events to constrain the profile of the Alfven speed in the lower corona. We show that the Alfven speed profile from global MHD models with ad hoc heating is not aligned with these observations, but that local (one dimensional) models with physically-motivated Alfven wave dissipation as a heating mechanism were in agreement. In the second part of the thesis, we study the resonant absorption of surface Alfven waves (SAW), a process which heats the solar wind. It is driven by a transverse gradient in the local Alfven speed (in relation to the magnetic field direction). In the solar corona, we expect this mechanism to occur at the boundaries of open and closed magnetic fields. We make the first estimation of SAW energy dissipation in the solar corona and find that it is comparable to the ad hoc heating a polytropic model at the boundary of open and closed magnetic fields and in subpolar open field regions. Next, we implemented the SAW damping mechanism into the new solar corona component of the Space Weather Modeling Framework, in which Alfven wave energy transport is self-consistently coupled to the MHD equations. The model already included wave dissipation along open magnetic field lines, mimicking turbulence. We demonstrate that including SAW dissipation in the model improved agreement with observations of coronal temperature both near the Sun and in the inner heliosphere by comparing with data from Ulysses and the Solar Terrestrial Relations Observatory (STEREO). Also, the inclusion of SAW dissipation steepened the Alfven speed profile in the lower corona, aligning the Alfven profile better with observational constraints of shock formation. In the final part of the thesis, we modeled a CME in this newly developed solar wind background, and studied the interaction between the CME and the wind. We generate the eruption with a flux rope. We constrain the parameters of the flux rope with data from the 13 May 2005 eruption, including H-alpha images of the pre-eruption magnetic field, coronagraph images of the CME's shape and velocity. Because the flux rope traveled faster than the local magnetosonic speed, it acted as a piston and drove a shock wave ahead of it. The CME-driven shock had a strong impact on the solar wind environment through which it propagates: it altered the wave energy by concentrating it in the sheath through advection, and also increasing its value through momentum transfer. This simulation demonstrated how Alfven waves are focused into the sheaths of ICMEs. The wave energy is then dissipated at the shock due to SAW damping. The shock heating accounted for 10% of the total change in thermal energy of the CME. The resulting temperature distribution of the CME is more aligned with observations than from a CME modeled in a polytropic solar wind. This thesis has improved our understanding of the interaction between a CME and the solar wind through which it propagates. Our picture of CME-evolution in the lower corona will be tested by future missions Solar Probe (which will sample this region directly) and the Solar Orbiter.
Author: David Burgess
Publisher: Springer
ISBN: 9781461464617
Category : Science
Languages : en
Pages : 0
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Book Description
This volume explores the cross-linkages between the kinetic processes and macroscopic phenomena in the solar atmosphere, which are at the heart of our current understanding of the heating of the closed and open corona and the acceleration of the solar wind. The focus lies on novel data, on theoretical models that have observable consequences through remote sensing, and on near-solar and inner-heliosphere observations, such as anticipated by the upcoming Solar Orbiter and Solar Probe missions, which are currently developed by the international community. This volume is aimed at students and researchers active in solar physics and space science. Previously published in Space Science Reviews journal, Vol. 172, Nos. 1-4, 2012.
Author: Andreas Keiling
Publisher: John Wiley & Sons
ISBN: 1119055024
Category : Science
Languages : en
Pages : 528
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Book Description
Low-frequency waves in space plasmas have been studied for several decades, and our knowledge gain has been incremental with several paradigm-changing leaps forward. In our solar system, such waves occur in the ionospheres and magnetospheres of planets, and around our Moon. They occur in the solar wind, and more recently, they have been confirmed in the Sun’s atmosphere as well. The goal of wave research is to understand their generation, their propagation, and their interaction with the surrounding plasma. Low-frequency Waves in Space Plasmas presents a concise and authoritative up-to-date look on where wave research stands: What have we learned in the last decade? What are unanswered questions? While in the past waves in different astrophysical plasmas have been largely treated in separate books, the unique feature of this monograph is that it covers waves in many plasma regions, including: Waves in geospace, including ionosphere and magnetosphere Waves in planetary magnetospheres Waves at the Moon Waves in the solar wind Waves in the solar atmosphere Because of the breadth of topics covered, this volume should appeal to a broad community of space scientists and students, and it should also be of interest to astronomers/astrophysicists who are studying space plasmas beyond our Solar System.
Author: Eric Priest
Publisher: Cambridge University Press
ISBN: 110778266X
Category : Science
Languages : en
Pages : 581
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Book Description
Magnetohydrodynamics of the Sun is a completely new up-to-date rewrite from scratch of the 1982 book Solar Magnetohydrodynamics, taking account of enormous advances in understanding since that date. It describes the subtle and complex interaction between the Sun's plasma atmosphere and its magnetic field, which is responsible for many fascinating dynamic phenomena. Chapters cover the generation of the Sun's magnetic field by dynamo action, magnetoconvection and the nature of photospheric flux tubes such as sunspots, the heating of the outer atmosphere by waves or reconnection, the structure of prominences, the nature of eruptive instability and magnetic reconnection in solar flares and coronal mass ejections, and the acceleration of the solar wind by reconnection or wave-turbulence. It is essential reading for graduate students and researchers in solar physics and related fields of astronomy, plasma physics and fluid dynamics. Problem sets and other resources are available at www.cambridge.org/9780521854719.
Author: E. Marsch
Publisher: Elsevier
ISBN: 1483287807
Category : Science
Languages : en
Pages : 740
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Book Description
The third COSPAR Colloquium entitled Solar Wind Seven was held in Goslar, Germany in September 1991. Twenty-two countries were represented by scientists, many of whom are leading experts in the area of heliospheric physics. The Proceedings reflect current research on solar wind and particularly emphasizes the source regions. The main topics covered encompass Coronal Heating and Solar Wind Acceleration; Large-Scale Structure of the Interplanetary Medium; Minor Ions, Neutrals and Cosmic Rays in the Heliosphere; Kinetic Physics, Waves and Turbulence and finally Heliospheric Dynamic Phenomena.
Author: J. R. Jokipii
Publisher: University of Arizona Press
ISBN: 0816538638
Category : Science
Languages : en
Pages : 1048
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Book Description
Until the advent of space physics, astrophysical plasmas could be studied only using ground-based observations. Although observational methods have advanced over recent decades, the merging of heliospheric physics with astrophysics is far from complete due to the vastly different techniques employed by astronomers and space physicists. That astrophysical plasmas can be studies directly is a major advance in astrophysical research. The solar wind from the Sun is only one of many examples of solar winds, but it provides scientists with a basis for understanding how these formerly disparate disciplines are related. Cosmic Winds and the Heliosphere is a comprehensive sourcebook on conceptually correlated topics in astrophysical winds and heliospheric physics. The contributors review the various kinds of winds, such as solar wind, winds of cataclysmic variables, and winds from pulsating stars. They then examine the physics of wind origin and physical phenomena in winds. including heliospheric shocks, magnetohydrodynamic turbulence, and kinetic phenomena. A final section considers interactions with surrounding media, with contributions ranging from studies of the interstellar cloud surrounding the solar system to considerations of solar wind interaction with comets. Prepared to the scrupulous standards of the University of Arizona Space Science Series, Cosmic Winds and the Heliosphere is an essential volume for astronomers and space physicists.
