Download or read book The Magnetospheric Constellation Mission Dynamic Response and Coupling Observatory DRACO Understanding the Global Dynamics of the Structured Magnetotail written by and published by . This book was released on 2001 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Magnetospheric Constellation Mission written by and published by . This book was released on 2002 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Magnetospheric Constellation Mission Dynamic Response and Coupling Observatory draco Understanding Th Nasa written by United States. National Aeronautics and Space Administration and published by . This book was released on 2003* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The magnetospheric constellation mission written by and published by . This book was released on 2002 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Application Science for Multi Agent Systems written by Thomas A. Wagner and published by Springer Science & Business Media. This book was released on 2006-04-11 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: An Application Science For Multi-Agent Systems addresses the complexity of choosing which multi-agent control technologies are appropriate for a given problem domain or a given application. Without such knowledge, when faced with a new application domain, agent developers must rely on past experience and intuition to determine whether a multi-agent system is the right approach, and if so, how to structure the agents, how to decompose the problem, and how to coordinate the activities of the agents, and so forth. This unique collection of contributions, written by leading international researchers in the agent community, provides valuable insight into the issues of deciding which technique to apply and when it is appropriate to use them. The contributions also discuss potential trade-offs or caveats involved with each decision. An Application Science For Multi-Agent Systems is an excellent reference for anyone involved in developing multi-agent systems.
Download or read book The Magnetospheric Constellation Mission written by and published by . This book was released on 2002 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Magnetospheric Constellation Mission Etc NP 2002 5 457 GSFC written by and published by . This book was released on 2002 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar Wind magnetosphere Coupling a Global Perspective of Reconnection in the Magnetotail written by Miles Thomas Bengtson and published by . This book was released on 2017 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a case study of the 25 December 2015 substorm which occurred between 08:15 and 08:45 Universal Time. During this interval, fast particle flows and field geometry consistent with magnetic reconnection were detected in the mid-tail region. An ejected plasmoid was observed by the lunar-orbiting Acceleration, Reconnection, Turbulence and Electrodynamics of Moon's Interaction with the Sun (ARTEMIS) probes and corresponding dipolarization signature was observed by the Time History of Events and Macroscale Interactions During Substorms (THEMIS) spacecraft earthward of the reconnection site, which was determined to be approximately -33 RE Ground signatures indicative of substorm activity were also observed by the THEMIS ground-based observatories during this interval. Prior to the sub- storm, none of the solar-wind monitoring missions (Geotail, OMNI, ACE) observed a significant southward Bz, which could have initiated the event. The Magnetospheric Multiscale (MMS) spacecraft, which were in the day-side magnetosheath, detected a strong pulse in Bz with a minimum near -35 nT, at ~08:05 UT, consistent with the time delay required for propagation from the magnetosheath to the mid-tail. We propose that this pulse is either a small-scale structure in the solar wind, the result of a kinetic shock process due to a solar wind discontinuity hitting the bow shock, or a flux-transfer event at the magnetopause and, further, that this strong southward component of Bz, in the magnetosheath is associated with the trigger of the observed substorm. We simulate the entire magnetosphere in maximum detail for this event using the Space Weather Modeling Framework/Block Adaptive Tree Solar-wind Roe Upwind Scheme (SWMF/BATS-R-US) model from NASA's Community Coordinated Modeling Center (CCMC) with a special, high- resolution grid. The results of this work will be highly relevant to future solar wind observation missions, global-scale magnetohydrodynamic models, and the ongoing effort to understand how processes at lunar distances in the tail couple to the rest of the near-Earth space environment.
Download or read book Dayside Aurora and Its Connection to the Solar Wind Magnetosphere Ionosphere Interaction written by Boyi Wang and published by . This book was released on 2018 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a comprehensive study of the dayside auroral dynamics and remote sensing of coupled magnetosphere-ionosphere system responses to various upstream disturbances, which include interplanetary magnetic field (IMF) discontinuities, foreshock transients, and magnetosheath high speed jets (HSJs). Recent studies have shown that these disturbances have significant impacts on coupled magnetosphere-ionosphere system, changing the particle transportation and energy budget. However, it has been difficult to find spatial structure and evolution of the interaction processes using a limited number of in-situ measurements. This dissertation aims to understand how dayside aurora and airglow respond to upstream disturbances, and to utilize auroral imaging to determine how the magnetosphere-ionosphere system responds to the upstream disturbances. Our study takes a unique approach by taking advantage of high-resolution 2D imaging to vastly increase community's understanding of magnetosphere-ionosphere responses to upstream disturbances, through tracing location, size and propagation of optical structures. We first examine the role of IMF southward turnings as the trigger of Poleward Moving Auroral Forms (PMAFs), which are thought to be an ionospheric signature of dayside magnetic reconnection. While PMAFs are more likely to occur when the IMF is southward, how often PMAFs are triggered by changes in solar wind parameters is still a major open question and has only been poorly understood due to the use of solar wind monitors far away from the bow shock. This dissertation addresses this question with the conjunction between the all-sky imager (ASI) at Automatic Geophysical Observatories (AGO) P1 station in Antarctica and the Time History of Events and Macroscale Interactions during Substorms (THEMIS) B and C satellites, which provide much more accurate solar wind conditions than the solar wind monitors at the L1 point. In a statistical study using 60 PMAF events, 70% of the events show a reduction of IMF Bz before PMAF onset, which indicates that IMF southward turning plays an important role in triggering a majority of PMAFs. Those PMAFs were further found to evolve to polar cap airglow patches. This dissertation investigates how often polar cap patches originate in PMAFs and are associated with flow channels, using the conjunction between the ASI at the AGO P1 station and DMSP satellites. Our 50-event statistical study shows that in a majority (45) of events, longitudinally narrow flow enhancements directed anti-sunward are found to be collocated with the patches, have velocities (up to a few km/s) substantially larger than the large-scale background flows (~500 m/s) and have widths comparable to patch widths (~400 km). The patches emanated out of PMAFs and were found to have a large IMF By dependence on the MLT of patches entering the polar cap. Through investigation of dayside aurora, we noticed that auroral brightenings can occur even without substantial changes in the IMF Bz or dynamic pressure. We examined whether disturbances generated in the foreshock and magnetosheath can contribute to dayside auroral brightening. Studies of the impact of foreshock and magnetosheath transients on the magnetosphere-ionosphere system are very limited, and it has been difficult to find how the transients interact in individual events due to limited in-situ and space-based imaging observations. In this dissertation, the conjunction between the ASI at South Pole and the THEMIS satellites during 2008 through 2011 is utilized to determine the magnetosphere-ionosphere responses to foreshock transients and magnetosheath HSJs in a 2D perspective. In situ observation by the THEMIS satellites showed that a foreshock transient during 1535-1545 UT on 25 June 2008 was associated with magnetospheric compression. The ASI at South Pole observed that both diffuse and discrete aurora brightened locally soon after the appearance of this foreshock transient. With the advantage of the high-resolution 2D imaging, we were able to determine that the diffuse auroral brightening corresponds to a localized azimuthal extent of a few Re size on the equatorial plane, and propagated duskward with an average speed of ~100 km/s. Similarly, we for the first time show a nearly one-to-one relationship between the HSJs and individual localized discrete/diffuse auroral brightenings using eight HSJ events. The azimuthal size of HSJ-related diffuse auroral signatures is ~800 km at 230-km altitude in the ionosphere and ~3.7 Re in the magnetosphere, which is slightly larger but of the order of the cross-sectional diameter of HSJs (~1 Re). Furthermore, most of those auroral signatures have azimuthal motions, whose magnitude and direction agree with magnetosheath background flows. In addition to magnetospheric compression, foreshock transients were also found to cause Pc5-band (150-600s) ultra-low frequency (ULF) waves, which are important in transporting mass, energy and momentum in the coupled magnetosphere-ionosphere system. Although it is difficult to find spatial structure of dayside Pc5 waves by a small number of satellites or ground magnetometers, we have successfully determined the 2D structure and motion of ULF waves in the ionosphere using optical imagers. This dissertation reports two series of foreshock-driven Pc5 waves, which are found to be field line resonances (FLRs). The ground-based ASI at South Pole shows that periodic poleward moving east-west arcs are the ionospheric signature of FLRs. The azimuthal distribution, including dawn-dusk symmetricity and azimuthal wavenumbers, of the FLRs in the magnetosphere, are further determined by 2D imaging. The fine structure embedded in the large-scale arcs indicates a wave with high toroidal wavenumber (m ~ 140) was coupled with the FLRs. Based on these works, a likely scenario revealed from the satellite-imaging coordinated observations is as follows: Foreshock transients and magnetosheath HSJs drive compressions of the magnetopause at a few RE, much more localized than global compression by shocks. The compressions launch fast-mode waves and FLRs, which create localized electron precipitation and auroral brightenings. The auroral responses found in this study can highlight structure and evolution of the magnetospheric and ionospheric responses, and signify the geoeffectiveness of localized and transient upstream energy input.
Download or read book GPS Total Electron Content Techniques for Observing the Structure and Dynamics of the High Latitude Ionosphere written by Chris Watson and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The solar wind, magnetosphere and ionosphere (SW-M-I) constitute a highly coupled system, where solar wind energy drives dynamic processes of the magnetospheric cavity and embedded ionosphere. The high latitude ionosphere has an inherently complex structure and dynamic behavior due to direct coupling to the solar wind and outer magnetosphere. Energy and charged particles deposited in the high latitude ionosphere via SW-M-I coupling processes generate ionization structures with variable spatial scales and dynamic behavior. Characteristics of ionization structures, such as their source, generation mechanisms, and evolution, are not well understood, largely due to past inadequacies in observational capabilities at high latitudes. From a physics perspective, the observation of high latitude ionospheric processes and structures is a proven technique for studying physical processes in the magnetosphere and solar wind. From an industrial and societal perspective, the dynamic high latitude ionosphere is potentially problematic due to significant impacts on electromagnetic signals used for navigation and communication. Recent installation of high data rate Global Positioning System (GPS) receivers of the Canadian High Arctic Ionospheric Network (CHAIN) has provided new, high resolution observations of the high latitude ionosphere. This thesis uses a statistical study and case studies to investigate the characteristics and source regions of ionospheric total electron content (TEC) variations observed by CHAIN GPS receivers. In the statistical study, occurrence rate, amplitude, and frequency of TEC variations were examined, in order to investigate the dependence of these characteristics on magnetic local time, latitude, and solar wind conditions. In three case studies, variations in TEC resulting from ultra-low frequency (ULF) waves in Earth’s geomagnetic field were observed. It is shown that GPS TEC has a significant response to various ULF wave classifications and intensities, and is a potentially valuable tool for high resolution study of ULF activity and the associated ionospheric response.
Download or read book Magnetospheric Multiscale written by James L. Burch and published by Springer. This book was released on 2016-12-16 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: NASA’s Magnetospheric Multiscale (MMS) mission is a four-spacecraft Solar Terrestrial Probe mission to study magnetic reconnection, a fundamental plasma physical process in which energy stored in a magnetic field is converted into the kinetic energy of charged particles and heat. The driver of eruptive solar events such as flares and coronal mass ejections, magnetic reconnection is also the process by which energy is transferred from the solar wind to Earth’s magnetosphere. Flying in a tetrahedral formation, the four identically instrumented MMS spacecraft measure the plasma, electric and magnetic fields, and energetic particles in the regions of geospace where magnetic reconnection is expected to occur. With interspacecraft distances varying from 400 km to 10 km and instruments capable of making extremely fast measurements (30 ms for electrons), MMS has the spatial and temporal resolution needed to resolve for the first time the microphysics of the electron diffusion region. Here, the magnetic field and the plasma become decoupled, allowing reconnection to occur. During the first of its two mission phases, MMS targets the dayside magnetopause, where the interplanetary and terrestrial magnetic fields reconnect. In the second phase, MMS increases its apogee from 12 RE to 25 RE and probes the nightside magnetosphere, where energy stored in the stretched field lines of the magnetotail is explosively released in magnetospheric substorms. Launched in March 2015 into a low-inclination elliptical orbit, MMS is now in Phase 1 of science operations. This volume, which describes the MMS mission design, observatories, instrumentation, and operations, is aimed at researchers and graduate students in magnetospheric physics and plasma physics. Researchers using the publicly available MMS data will find it particularly useful. Previously published in Space Science Reviews, Volume 199, Nos. 1-4, 2016.
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 Analysis and Visualization of Global Magnetospheric Processes written by and published by . This book was released on 1998 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The purpose of this project is to develop new computational and visualization tools to analyze particle dynamics in the Earth's magnetosphere. These tools allow the construction of a global picture of particle fluxes, which requires only a small number of in situ spacecraft measurements as input parameters. The methods developed in this project have led to a better understanding of particle dynamics in the Earth's magnetotail in the presence of turbulent wave fields. They have also been used to demonstrate how large electromagnetic pulses in the solar wind can interact with the magnetosphere to increase the population of energetic particles and even form new radiation belts.
Download or read book Solar Physics and Terrestrial Effects written by Roger P. Briggs and published by . This book was released on 1993 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar Wind Magnetosphere Coupling written by Y. Kamide and published by Springer. This book was released on 1986-11-30 with total page 832 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on papers from an AGU Chapman Conference on Solar Wind-Magnetosphere Coupling, held at the Jet Propulsion Laboratory of the California Institute of Technology, Pasadena, Calif., Feb. 12-15, 1985.
Download or read book Connecting Quarks with the Cosmos written by National Research Council and published by National Academies Press. This book was released on 2003-03-12 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances made by physicists in understanding matter, space, and time and by astronomers in understanding the universe as a whole have closely intertwined the question being asked about the universe at its two extremesâ€"the very large and the very small. This report identifies 11 key questions that have a good chance to be answered in the next decade. It urges that a new research strategy be created that brings to bear the techniques of both astronomy and sub-atomic physics in a cross-disciplinary way to address these questions. The report presents seven recommendations to facilitate the necessary research and development coordination. These recommendations identify key priorities for future scientific projects critical for realizing these scientific opportunities.
Download or read book Celestial Delights written by Francis Reddy and published by Springer Science & Business Media. This book was released on 2011-11-12 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Celestial Delights is essentially a 'TV Guide' for teh sky. This will be its third edition. This title, which has aggregated sales of about 20,000 copies to date in its two previous editions and has found a niche with skygazers, is much awaited. Through extensive graphics integrated with an eight-year-long calendar of sky events, it provides a look at "don't miss" sky events, mostly for naked-eye and binocular observing. The book is organized by ease of observation - lunar phases and the brighter planets come first, while solar eclipses, the aurora, and comets come later. Celestial Delights also includes a hefty dose of sky lore, astronomical history, and clear overviews of current science. It provides a handy reference to upcoming naked-eye events, with information broken out in clear and simple diagrams and tables that are cross-referenced against a detailed almanac for each year covered. Most broad-ranging astronomy field guides focus on stars, constellations, and the deep sky, but tend to ignore planetary events, which are in by far the most widely observable aspects of the changing night sky. Celestial Delights puts a variety of information all in one place, presents it in a friendly way that does not require prior in-depth astronomical knowledge, but provides the context and historical background for understanding events that astronomical computer programs or web sites lack.
