Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"magnetotail"”.
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Solar Wind-Magnetosphere Coupling: A Global Perspective of Reconnection in the Magnetotail
<p>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 …
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Non-adiabatic features in magnetotail fast flows: Orbit tracing and data comparisons
… electric field configurations. Fast flows in the magnetotail are selected to be modeled using a relatively thin current sheet compared with quiet times. Four different electric fields are imposed, varying in characteristic thickness and magnitude. Using these four particle based models we were …
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The Study of Magnetotail Dynamics and their Ionospheric Signatures using Magnetohydrodynamic Simulation Model: OpenGGCM
In-situ measurements in the magnetotail are sparse and limited to single points. In the ionosphere, on the other hand, there is a broad range of observations, including magnetometers, aurora imagers, and radars . Since the ionosphere is the mirror of the plasmasheet, it can be used as a monitor of …
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Quantitative modeling of time-dependent phenomena in the magnetospheric magnetic field
… current strength and orientation over the entire magnetotail length. Revision of the tail shielding/interconnection field eliminates inconsistencies in the model magnetotail, and permits variation in the normal component distribution over the tail portion of the magnetopause. The enhanced …
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MODELING OF PLASMA-SHEET CONVECTION: IMPLICATIONS FOR SUBSTORMS (MAGNETOSPHERE)
… and magnetic energy accumulate in the Earth's magnetotail to be released in sporadic events, namely substorms. It is shown that the idea of steady convection is inconsistent with the idea of slow, approximately lossless, plasma convection in a long, closed-field-line region that extends into a …
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Global Structure of the Nightside Proton Precipitation during Substorms using Simulations and Observations
… brings magnetic flux from the highly stretched magnetotail into the near earth magnetosphere. Once there, the flux piles up forming an azimuthally localized region where the magnetic field is more dipolar. Current flows into and out of the ionospere at the edges of this dipolarized region …
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Statistical study of oxygen+ transport from the cusp to the plasmasheet
… frequency of the cusp-source O+ in the magnetotail to determine where and when it is observed. The results show that the probability to observe O+ along the transport path is high even during nonstorm times, although, as expected, the highest probability is found during storm times. In …
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A Method to Compute Three Dimensional Magnetospheric Equilibria with Dipole Tilt and its Application in Estimating Magnetic Flux Tube Volume
… for calculating magnetic flux tube volume in the magnetotail, in an attempt to generalize the Wolf [2006] empirical formula, and describe a method for estimating flux tube volume from measurements at geosynchronous orbit. This new method has been tested against various equilibrated magnetospheres …
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Solar Wind-Magnetosphere-Ionosphere Coupling: Multiscale Study with Computational Models
… the kinetic scale dynamics associated with the magnetotail dipolarization front (DF), which is generated as a result of magnetotail reconnection. The PIC study demonstrates that the electron-ion hybrid (EIH) instability could relax the velocity shear within the DF via emitting lower hybrid …
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Structure of the electron diffusion region in magnetic reconnection with small guide fields
Observations in the Earth's magnetotail and kinetic simulations of magnetic reconnection have shown high electron pressure anisotropy in the inflow of electron diffusion regions. This anisotropy has been accurately accounted for in a new fluid closure for collisionless reconnection. By tracing …
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Modeling the formation of current sheets in symmetric and asymmetric reconnection
… the reconnection layer relevant to the Earth magnetotail, as well as configurations asymmetric in density and temperature across the reconnection layer, important to reconnection in Earth's dayside magnetopause. We develop an analytic model for the evolution of the electron phase space …
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Setting Constraints on the Lunar Exosphere: A Comprehensive Analysis of Velocity Resolved Sodium and Potassium Line Profile Measurements
… ions in the response of the exosphere during magnetotail passage. A large part of this work is focused on the analysis of sodium and potassium based on the near lunar plasma environment: (i.e., solar wind, magnetosheath, and magnetotail) as a function of latitude. Sodium exospheric …
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"Smoking-Gun" Observables of Magnetic Reconnection: Spatiotemporal Evolution of Electron Characteristics Throughout the Diffusion Region
… Cluster spacecraft measurements from a magnetotail reconnection exhaust region agree with these simulation predictions. In PIC simulations of asymmetric reconnection, EDR distributions acquire crescent-shaped populations, indicative of accelerated magnetosheath electrons mixing with …
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A Three-Year Study of the Magnetic Field Fluctuations in the Magnetospheric Cusp
… and possibly the earthward propagation of magnetotail reconnection fluctuations. Sources of wave power from 0.017-0.1 Hz include mirror mode, ion-cyclotron, and Alfven waves. Sources of wave power from 0.1-10 Hz include ion-cyclotron and Alfven waves.</p>
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Ionospheric Convection and Auroral Responses to Solar Wind Driving
… flux, which eventually reconnects in the magnetotail. When dayside reconnection is dominant, the polar cap, the area where open magnetic flux meets the Earth's surface, increases. Similarly, when nightside reconnection is dominant, the polar cap decreases in size. This framework is known …
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Ionospheric Disturbances: Midlatitude Pi2 Magnetospheric ULF Pulsations and Medium Scale Traveling Ionospheric Disturbances
… plasma flows were detected by spacecraft in the magnetotail. Signatures of inner magnetospheric compression observed by the Blackstone radar provide conclusive evidence that the plasma flow bursts directly generated the ground Pi2 signature via a compressional wave. This mechanism had previously …
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Driving Influences of Ionospheric Electrodynamics at Mid- and High-Latitudes
… all substorms, and preconditioning of the magnetotail may be an important factor.
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Occurrence Statistics and Driving Mechanisms of Ionospheric Ultra-Low Frequency Waves Observed by SuperDARN Radars
… ionosphere; and, (ii) a source associated with magnetotail dynamics during active geomagnetic times is suggested for Pc3-4/Pi2 waves at midlatitudes in the nightside ionosphere. These findings are further expanded in Chapter 4 which investigates the hypothesis that internal wave-particle …
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MMS Observations of the Kelvin-Helmholtz Instability and Associated Ion Scale Waves
… at the dayside magnetopause and in the magnetotail. It comprises 4 identical spacecraft, which fly in formation and are equipped with the highest resolution instrumentation available. MMS is the first mission capable of resolving electron scale processes due to its combination of high …
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