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 33 for “"Velocity space"”.
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The Velocity-Space Particle Loss in Field-Reversed Theta Pinches
… are not well known. In this work, we study the velocity-space particle loss (VSPL), i.e., particle loss due to the existence of a loss region in velocity space, in FRTP's in order to have a better understanding about the characteristics of this device.
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Electron velocity-space diffusion in a micro-unstable ECRH mirror plasma
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1988.
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An Alpha Loss-Cone Instability in the Central Cell of a Tandem Mirror Reactor
… loss-cone distribution of the alpha particles in velocity space is capable of destabilizing low frequency plasma waves, thus affecting the energy balance in a tandem mirror plasma.
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STABILITY OF UPGOING AURORAL ION BEAMS AT 33 R(E) (PLASMA, MAGNETOSPHERE, WAVE-PARTICLE INTERACTIONS)
… or above the cold ionospheric source region. Velocity space distributions of the two ion species show hydrogen having a higher streaming velocity than oxygen, but also a smaller streaming energy. The region of velocity space between the two ion beam peaks has been filled in, with ions in the …
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Discontinuous Galerkin solutions of the Boltzmann equation: spectral collocation and moment methods
… description of moving particles, which relies on space, time, and velocity variables. Two novel approaches are presented and compared. The first uses a spectral collocation basis in velocity space. The resulting system is solved in time using Diagonally Implicit Runge-Kutta methods, chosen in …
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Collaborative internet and voice data transfer using bluetooth mesh networking
… algorithm, making use of a quantized hop velocity space to lower the probability of two devices missing each other completely during discovery, and introduce the concept of redundant backup paths to the wireless mesh, allowing for improved reliability in dynamic mesh network situations.
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Geometria finsler e incêndios florestais.
… the propagation of wildfires considers that the velocity space is represented by an indicatrix at each point. Since then, elliptic modeling has been widely accepted. In A general model for wildfire propagtion with wind and slope, Javaloyes (2023) presents a more sophisticated model for fire …
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Fuel-optimal space-flight transfer solutions through a redundant adjoint variable transformation
… variables associated with Cartesian position and velocity vectors and a set of redundant adjoint variables associated with certain regularized variables (Schumacher variables). This transformation proves to be very beneficial when it is applied to minimum-fuel space rendezvous and intercept …
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Theoretical and Numerical Studies of Frequency Up-shifted Ionospheric Stimulated Radiation
… spectrum observed during the experiments. The velocity-space ring-plasma instability, another generation mechanism for the BUM spectra, is studied using a theoretical model. The theoretical calculations show that the growth rate is larger in the region of the upper hybrid wave than that of the …
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Orbital effects on pitch angle diffusion of injected fast-ion beams in tokamaks
… equation is taken, yielding a solution in velocity space variables velocity and pitch angle. In the first case, conditions in the form of a linear combination of co, counter, and trapped distributions or fluxes are matched at the orbit transition value of pitch angle so that several …
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Non-adiabatic features in magnetotail fast flows: Orbit tracing and data comparisons
<p>The purpose of this study is to investigate velocity space distribution functions in space plasmas. Orbit tracing methods are used to generate self-consistent models of several different magnetic and electric field configurations. Fast flows in the magnetotail are selected to be modeled using a …
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Electron equations of state during magnetic reconnection
… dynamics. Particularly in collisionless plasmas, velocity-space anisotropy of the electrons plays a leading role in governing the energy exchanges and shaping the currents that develop during reconnection. The anisotropy results from an electric field parallel to the magnetic field that tends to …
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Fully kinetic numerical modeling of a plasma thruster
… equation for the particle trajectories in velocity space. Ion-electron recombination was modeled at the boundaries, and neutrals were recycled into the flow. The cathode was modeled indirectly by inject- ing electrons at a rate which preserved quasineutrality. Anomalous diffusion was …
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High Reynolds Number Turbulent Boundary Layer Flow over Small Forward Facing Steps
… wall pressure fluctuations, single and 2 point velocity fluctuations and, oil flow visualization. Pressure fluctuation measurements were made 5 boundary layer thicknesses upstream of step to 22 boundary layer thickness (or 600 step heights for smallest step size) downstream of the step. The …
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"Smoking-Gun" Observables of Magnetic Reconnection: Spatiotemporal Evolution of Electron Characteristics Throughout the Diffusion Region
… reconnection, the spatiotemporal evolution of velocity distribution functions in and around the electron diffusion region (EDR) elucidates how electrons are accelerated and heated by the cooperating reconnection electric and normal magnetic fields. The discrete, triangular structures …
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Modeling reactive rarefied systems using a novel quasi-particle Boltzmann solver
… describes a system with a discretized, truncated velocity distribution function. The resulting fixed-velocity, variable weight quasi-particles enable smooth variation of macroscopic properties. The distribution function description enables use of a variance reduced collision model, greatly …
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Fully-kinetic PIC simulations for Hall-effect thrusters
… functions within individual cells to ensure full velocity space coverage. A non-Monte Carlo collision technique was also implemented to reduce statistical noise.
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Advances in fully-kinetic PIC simulations of near-vacuum Hall thruster and other plasma systems
… functions within individual cells to ensure full velocity space coverage.
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Comparison of Linear, Nonlinear, Hysteretic, and Probabilistic MR Damper Models
… with a static model dependent on current and velocity. This study will compare different techniques for modeling the force response of the damper in the current-velocity space. To ensure that all the dynamic response characteristics of the damper are captured in data collection, random input …
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An investigtion into the ability of a kinetic particle-based solver for study of gas flows in micro-scale structures
… liberal approximations such as restricting the velocity space to a limited set determined through pre-cognizance or trials. Even stochastic particle approaches, such as the DSMC, usually adept at resolving such flows, proves to be prohibitively expensive owing to the small signal to-noise ratio …
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