Download or read book A Study of the Viscous Interaction Between the Solar Wind and Earth s Magnetosphere Using an MHD Simulation written by Robert Jeffrey Bruntz and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The solar wind interacts with Earth's magnetosphere largely through magnetic reconnection and a "viscous-like" interaction that is not fully understood. The ionospheric cross-polar cap potential ([phi]PC) component due to reconnection ([phi]R) is typically much larger than the viscous component ([phi]V) and very dynamic, making detailed studies of the viscous potential difficult. We used the Lyon-Fedder-Mobarry (LFM) magnetohydrodynamic (MHD) simulation to study the viscous potential by running LFM for a variety of solar wind density and velocity values and ionospheric Pedersen conductance ([sigma]P) values, but no solar wind magnetic field, so that [phi]PC was entirely due to the viscous interaction. We found that [phi]V increased with solar wind density, scaling as n0.439 (n in cm-3), and [phi]V increased with solar wind velocity, scaling as V1.33 (V in km s-1); these results were combined to create a formula for [phi]V in LFM, using a [sigma]P value that produces realistic potentials: [phi]V = (0.00431)n0.439V1.33 (in kV), which matches simulation results very well. [phi]V also varied inversely with [sigma]P, as predicted by previous theory. The form of this formula is similar to results from the Newell et al. [2008] empirical study, which tested a list of viscous coupling functions and found that n1/2V2 worked best (but did not create a formula to predict potentials, so actual viscous potential values could not be compared). The Bruntz et al. formula was also compared to LFM results from a run with real solar wind input, from the Whole Heliosphere Interval (WHI), which lasted from 20 March to 16 April 2008. LFM was first run with the full solar wind from the WHI, then with the same solar wind but zero interplanetary magnetic field (IMF), which meant that [phi]PC = [phi]V for that run. These runs were performed with the empirical ionospheric solver, using the average F10.7 flux value from the WHI as input. This empirical ionosphere is known to produce potentials that are higher than observations, so the output was scaled down to match the range of the Bruntz et al. formula with a scaling factor y = 1.542, which was found from 11 steady periods in the WHI. Those same periods were also used to calibrate the Newell et al. viscous scaling factor, turning it into a predictive formula: [phi]V = (6.39 x10-5)n1/2V2 (in kV). Both viscous potential formulas were compared to [phi]PC from the zero-IMF run, producing [phi]V values that were very close to the LFM [phi]PC values, differing in opposite ways in some places, but with essentially identical correlation coefficients. We also used the y factor to scale [phi]PC from the full-IMF LFM run down, then compared it to [phi]PC from the Weimer05 empirical model. The two matched well in the higher [phi]PC values, but the Weimer05 [phi]PC values reached a minimum "floor" value, while the LFM [phi]PC has no such floor, and so dropped much lower in some places. The fact that y scaled the full-IMF LFM down to match the Weimer05 values, even though y was derived from very different runs and conditions, is interpreted to support the idea that the cause of high LFM potentials is in the ionospheric conductivity, since y is derived from the higher-conductivity-based Bruntz et al. formula.

Download or read book A Study of the Geospace Response to Dynamic Solar Wind Using the Lyon Fedder Mobarry Global MHD Simulation written by Richard E. F. Bonde and published by . This book was released on 2019 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the wind from the Sun advances towards Earth, it interacts with Earth's magnetic field. This solar wind carries with it a magnetic field, called the interplanetary magnetic field (IMF). Energy and momentum are transferred from the solar wind to the geospace environment through two mechanisms: magnetic reconnection between the IMF and Earth's magnetic field and a viscous-like interaction. While magnetic reconnection is the dominant mechanism, there are times when the viscous interaction has a significant contribution. Previous studies using magnetohydrodynamic (MHD) simulations to study the viscous interaction have done so using steady state solar wind conditions. The solar wind is highly dynamic and can have considerable changes on the order of minutes. We use the Lyon-Fedder-Mobarry global MHD simulation to test the effect the viscous interaction has on the transpolar potential (TPP) with solar wind velocity fluctuations. The TPP is used as a proxy for the amount of coupling between the solar wind and Earth's magnetosphere. While fluctuations in the equatorial plane seem to have little or no effect on the TPP, fluctuations in the meridional plane cause variations in the TPP, even creating an asymmetry between the hemispheres. The response the TPP was proportional to the amplitude of the velocity oscillation but appears not to be affected by the frequency of oscillation. There is also a strong flow asymmetry in the magnetotail, which is flapping like a wind sock, in response to these solar wind variations. This creates a large sunward flow in one of the two tail lobes. The effect of solar wind fluctuations can also be tested on the response to the dayside magnetopause. The dayside magnetopause position, regarded as a critical space weather metric, is of great importance to satellite operators. Large-scale fluctuations in the solar wind can compress the magnetopause inward over satellites, exposing them to the hazardous conditions in the magnetosheath. Again, previous studies on the magnetopause position were conducted with steady state solar wind conditions. We ran LFM to gauge the response of the subsolar magnetopause during conditions similar to a high-speed stream (HSS), where there are large Alfvénic fluctuations and the dynamic pressure is relatively constant. The dayside magnetopause responds to these IMF variations in a type of "breathing" mode. The subsolar magnetopause exhibits a hysteresis-like effect, having a roughly constant response time to an IMF perturbation with constantly changing IMF conditions. In certain situations, the subsolar magnetopause position never relaxes to steady state values. This shows that when running MHD simulations, the time history of the solar wind must be taken into account. A HSS from 14-19 September, 2017 was simulated in LFM to see the response of the dayside magnetopause. To verify the actual position of the dayside magnetopause during this event, a series of THEMIS magnetopause crossings were used. The THEMIS crossings, along with the LFM results, were compared to empirical models of the magnetopause. These empirical models use instantaneous solar wind parameters to predict the position of the magnetopause and at times were predicted to over 1 RE from the actual magnetopause position. The work presented in this dissertation shows that to improve the accuracy of empirical models, the time history of the solar wind cannot be overlooked.

Download or read book Solar wind Magnetosphere interaction written by Simon Wing and published by Frontiers Media SA. This book was released on 2023-07-05 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Mhd Study of the Interaction Between the Solar Wind and the Interstellar Medium written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-16 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall objective of this research program is to obtain a better understanding of the interaction between the solar wind and the interstellar medium through the use of numerical solutions of the time-dependent magnetohydrodynamic (MHD) equations. The simulated results have been compared with observations where possible and with the results from previous analytic and numerical studies. The primary accomplishment of this project has been the development of codes for 2-D models in both spherical and cylindrical coordinates and the application of the codes to the solar wind/interstellar medium interaction. Computations have been carried out for both a relatively simple gas-dynamic interaction and a flow-aligned interstellar magnetic field. The results have been shown to compare favorably with models that use more approximations and to modify and extend the previous results as would be expected. The simulations have also been used along with a data analysis study to provide a quantitative estimate of the distance to the termination and bow shocks. Some of the specific topics that have been studied are: (1) gas dynamic models of the solar wind/interstellar medium interaction, (2) termination shock response to large-scale solar wind fluctuations, and (3) distances to the termination shock and heliopause. The main results from each of these studies are summarized. The results were published in three papers which are included as attachments. Steinolfson, R. S. Unspecified Center NASA-CR-202458, NAS 1.26:202458 NAGw-2621; SwRI Proj. 15-4237...

Download or read book Earth s Magnetosphere written by Walter Heikkila and published by Elsevier. This book was released on 2011-10-13 with total page 535 pages. Available in PDF, EPUB and Kindle. Book excerpt: The author argues that, after five decades of debate about the interactive of solar wind with the magnetosphere, it is time to get back to basics. Starting with Newton's law, this book also examines Maxwell's equations and subsidiary equations such as continuity, constitutive relations and the Lorentz transformation; Helmholtz' theorem, and Poynting's theorem, among other methods for understanding this interaction. Includes chapters on prompt particle acceleration to high energies, plasma transfer event, and the low latitude boundary layer More than 200 figures illustrate the text Includes a color insert

Download or read book The Interaction Between the Solar Wind and the Earth s Magnetic Field written by S. Frankenthal and published by . This book was released on 1964 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report consists of a study of the interaction between the solar wind and the earth's magnetic field, which takes into account: (1) the presence of an interplanetary magnetic field within the solar wind, and (2) the possibility that the solar wind may be penetrated by field lines emanating from the earth. The first part of the report (Chapters I-IV) contains a qualitative discussion of the field and flow patterns which may develop under the conditions stated above. The second part of the report explores two methods for the treatment of the MHD equations which govern the interaction, namely, expansion in spatial coordinates, and parametric expansions. The first method, which is suitable for local studies of the flow, is applied to the region in the immediate vicinity of the stagnation line behind the bow shock. The results of this treatment are embodied in a local field-flow pattern, which reveals several features which can be attributed directly to the presence of an interplanetary field within the solar wind, weak as those fields may be.

Download or read book Magnetohydrodynamic Modeling of the Solar Corona and Heliosphere written by Xueshang Feng and published by Springer. This book was released on 2019-08-01 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Dayside Magnetosphere Interactions written by Qiugang Zong and published by John Wiley & Sons. This book was released on 2020-03-13 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exploring the processes and phenomena of Earth’s dayside magnetosphere Energy and momentum transfer, initially taking place at the dayside magnetopause, is responsible for a variety of phenomenon that we can measure on the ground. Data obtained from observations of Earth’s dayside magnetosphere increases our knowledge of the processes by which solar wind mass, momentum, and energy enter the magnetosphere. Dayside Magnetosphere Interactions outlines the physics and processes of dayside magnetospheric phenomena, the role of solar wind in generating ultra-low frequency waves, and solar wind-magnetosphere-ionosphere coupling. Volume highlights include: Phenomena across different temporal and spatial scales Discussions on dayside aurora, plume dynamics, and related dayside reconnection Results from spacecraft observations, ground-based observations, and simulations Discoveries from the Magnetospheric Multiscale Mission and Van Allen Probes era Exploration of foreshock, bow shock, magnetosheath, magnetopause, and cusps Examination of similar processes occurring around other planets The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.

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 Evolution and Motion of Transient Events in the Solar Wind magnetosphere Interaction written by Yaireska Marie Collado-Vega and published by . This book was released on 2013 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: Instabilities in the solar wind-magnetosphere interaction govern the entry of solar wind particles into the Earth's magnetosphere. These particles could ultimately be responsible for serious damage to our current technological systems. I use simulations and observations to investigate two kinds of instabilities that occur during unsteady interaction, magnetopause vortices and bursty reconnection resulting in flux transfer events (FTEs). For the magnetopause vortices analysis, magnetohydrodynamic (MHD) simulations were generated. Two cases were run, one for a nominal speed solar wind (360 km/s) and another for a high speed solar wind (700 km/s). Both cases had an abrupt change in the interplanetary magnetic field (IMF) orientation; 15 minutes being southward, -5 nT, and then turning northward, +5 nT, for two hours. No other parameter was changed in these runs. Using an IDL-based tool, I visualized the 2D and 3D nature of the vortices and compared my results with those obtained previously by Collado-Vega et al. (2007) who studied vortices using simulated MHD data initiated by real solar wind conditions. The characteristics of the vortices formed under dynamic solar wind conditions are consistent with vortices driven by surface waves on the magnetopause, like the Kelvin-Helmholtz (KH) instability. However, the majority of those developed under steady solar wind conditions suggest otherwise, especially the ones that developed on the dayside which are believed to be formed by the convection pattern created by high latitude reconnection. For the study of FTEs, I focus on Cluster satellite magnetopause encounters. The Cluster satellites orbit in a tetrahedral formation in near-polar orbits. I identified FTEs in Cluster observations from 2002 to 2003, and a total of 109 events were counted in the data set. A comparison of the analytical and global MHD simulation results indicates that most of the events form by component reconnection along a tilted subsolar reconnection line, move antisunward with the magnetosheath flow, and have long spatial extent. The events that were observed to have a motion opposite to the magnetosheath motion were found to have a strong By IMF component that can contribute to the flow reversal process.

Download or read book Magnetospheric Plasma Physics The Impact of Jim Dungey s Research written by David Southwood and published by Springer. This book was released on 2015-08-20 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book makes good background reading for much of modern magnetospheric physics. Its origin was a Festspiel for Professor Jim Dungey, former professor in the Physics Department at Imperial College on the occasion of his 90th birthday, 30 January 2013. Remarkably, although he retired 30 years ago, his pioneering and, often, maverick work in the 50’s through to the 70’s on solar terrestrial physics is probably more widely appreciated today than when he retired. Dungey was a theoretical plasma physicist. The book covers how his reconnection model of the magnetosphere evolved to become the standard model of solar-terrestrial coupling. Dungey’s open magnetosphere model now underpins a holistic picture explaining not only the magnetic and plasma structure of the magnetosphere, but also its dynamics which can be monitored in real time. The book also shows how modern day simulation of solar terrestrial coupling can reproduce the real time evolution of the solar terrestrial system in ways undreamt of in 1961 when Dungey’s epoch-making paper was published. Further contributions on current Earth magnetosphere research and space plasma physics included in this book show how Dungey’s basic ideas have remained explanative 50 years on. But the Festspiel also introduced some advances that possibly Dungey had not foreseen. One of the contributions presented in this book is on the variety of magnetospheres of the solar system which have been seen directly during the space age, discussing the variations in spatial scale and reconnection time scale and comparing them in respect of Earth, Mercury, the giant planets as well as Ganymede.

Download or read book The Atmosphere and Climate of Mars written by Robert M. Haberle and published by Cambridge University Press. This book was released on 2017-06-29 with total page 613 pages. Available in PDF, EPUB and Kindle. Book excerpt: Humanity has long been fascinated by the planet Mars. Was its climate ever conducive to life? What is the atmosphere like today and why did it change so dramatically over time? Eleven spacecraft have successfully flown to Mars since the Viking mission of the 1970s and early 1980s. These orbiters, landers and rovers have generated vast amounts of data that now span a Martian decade (roughly eighteen years). This new volume brings together the many new ideas about the atmosphere and climate system that have emerged, including the complex interplay of the volatile and dust cycles, the atmosphere-surface interactions that connect them over time, and the diversity of the planet's environment and its complex history. Including tutorials and explanations of complicated ideas, students, researchers and non-specialists alike are able to use this resource to gain a thorough and up-to-date understanding of this most Earth-like of planetary neighbours.

Download or read book Magnetohydrodynamic Waves in Geospace written by A.D.M. Walker and published by CRC Press. This book was released on 2019-09-12 with total page 1168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar-terrestrial physics deals with phenomena in the region of space between the surface of the Sun and the upper atmosphere of the Earth, a region dominated by matter in a plasma state. This area of physics describes processes that generate the solar wind, the physics of geospace and the Earth's magnetosphere, and the interaction of magnetospheri

Download or read book Astronomy and Astrophysics Abstracts written by S. Böhme and published by Springer Science & Business Media. This book was released on 2013-12-14 with total page 1180 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the reviews: Astronomy and Astrophysics Abstracts has appeared in semi-annual volumes since 1969 and it has already become one of the fundamental publications in the fields of astronomy, astrophysics and neighbouring sciences. It is the most important English-language abstracting journal in the mentioned branches. ... The abstracts are classified under more than hundred subject categories, thus permitting a quick survey of the whole extended material. The AAA is a valuable and important publication for all students and scientists working in the fields of astronomy and related sciences. As such it represents a necessary ingredient of any astronomical library all over the world." Space Science Reviews #1 "Dividing the whole field plus related subjects into 108 categories, each work is numbered and most are accompanied by brief abstracts. Fairly comprehensive cross-referencing links relevant papers to more than one category, and exhaustive author and subject indices are to be found at the back, making the catalogues easy to use. The series appears to be so complete in its coverage and always less than a year out of date that I shall certainly have to make a little more space on those shelves for future volumes." The Observatory Magazine #1

Download or read book A Three dimensional MHD Simulation of the Interaction of the Solar Wind with the Earth s Magnetosphere written by Tatsuki Ogino and published by . This book was released on 1984 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Dynamic Magnetosphere written by William Liu and published by Springer Science & Business Media. This book was released on 2011-06-21 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the plethora of monographs published in recent years, few cover recent progress in magnetospheric physics in broad areas of research. While a topical focus is important to in-depth views at a problem, a broad overview of our field is also needed. The volume answers to the latter need. With the collection of articles written by leading scientists, the contributions contained in the book describe latest research results in solar wind-magnetosphere interaction, magnetospheric substorms, magnetosphere-ionosphere coupling, transport phenomena in the plasma sheet, wave and particle dynamics in the ring current and radiation belts, and extra-terrestrial magnetospheric systems. In addition to its breadth and timeliness, the book highlights innovative methods and techniques to study the geospace.

Download or read book Multiscale Processes in the Earth s Magnetosphere From Interball to Cluster written by Jean-Andre Sauvaud and published by Springer Science & Business Media. This book was released on 2004-10-12 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past forty years of space research have seen a substantial improvement in our understanding of the Earth’s magnetosphere and its coupling with the solar wind and interplanetary magnetic ?eld (IMF). The magnetospheric str- ture has been mapped and major processes determining this structure have been de?ned. However, the picture obtained is too often static. We know how the magnetosphere forms via the interaction of the solar wind and IMF with the Earth’s magnetic ?eld. We can describe the steady state for various upstream conditions but do not really understand the dynamic processes leading from one state to another. The main dif?culty is that the magnetosphere is a comp- cated system with many time constants ranging from fractions of a second to days and the system rarely attains a steady state. Two decades ago, it became clear that further progress would require multi-point measurements. Since then, two multi-spacecraft missions have been launched — INTERBALL in 1995/96 and CLUSTER II in 2000. The objectives of these missions d- fered but were complementary: While CLUSTER is adapted to meso-scale processes, INTERBALL observed larger spatial and temporal scales. However, the number of papers taking advantage of both missions simul- neously is rather small.