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Showing 1 to 20 of 22 for “"Particle-In-Cell Simulations"”.
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Particle-in-cell simulations of perpendicular supernova shock fronts
The origin of cosmic rays was the subject of several studies for over a century. The investigations done within this dissertation are one small step to shed some more light on this mystery. Locating the sources of cosmic rays is not trivial due to the interstellar magnetic field. However, the …
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Immersed Finite Element Particle-In-Cell Simulations of Ion Propulsion
A new particle-in-cell algorithm was developed for plasma simulations involving complex boundary conditions. The new algorithm is based on the three-dimensional immersed finite element method which is developed in this thesis, and a modified legacy particle-in-cell code. The model also applies a …
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Particle-In-cell simulations of nonlocal and nonlinear effects in inductively coupled plasmas
The kinetic effects in an inductively coupled plasma (ICP) due to thermal motion of particles modified by self-consistent magnetic fields are studied by using a particle-in-cell (PIC) simulation. In the low pressure, low frequency regime, electron mean free paths are large relative to device size …
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Particle-in-Cell Simulations Examining AK Gap Closure Mechanisms in the Pinch Reflex Diode
Gap closure mechanisms in the pinch reflex diode are studied using cylindrical, two-dimensional, fully kinetic, electromagnetic, particle-in-cell simulations. The key physical dimensions in the model are based on the Mercury accelerator at the Naval Research Laboratory in Washington, DC. Simulation …
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Fully kinetic particle-in-cell simulations of plasma-surface-dust interactions for lunar exploration
<p>"The studies involving lunar surface explorations have drawn attentions in recent years. A better understanding of possible potential hazards to astronauts and electronic equipment has become a necessity for future lunar explorations. The lunar surface, lacking an atmosphere and global magnetic …
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Mass-spectroscopy and modeling of capacitive coupled hydrogen plasmas
… time-prole of the afterglow when RF power is terminated are investigated. Fluxes of the hydrogen ions, H+ , H+2, H+3, at the grounded electrode are measured with an energy-resolved mass spectrometer. Spatial proles of the electron density are measured using a hairpin probe. Particle-in-cell …
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Laboratory Astrophysics Studies of Magnetized Collisionless Shock Precursors and the ³He³He Proton Spectrum at the OMEGA Laser Facility
… enables the study of astrophysical systems in the lab. There are broadly two types of laboratory astrophysics experiments: macrophysics and microphysics. Macrophysics experiments study a scaled down version of an astrophysical system while microphysics experiments create a small volume of …
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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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Volumetric creation of ultra-high-energy-density plasma by irradiation of ordered nanowire arrays
Creating appreciable volumes of Ultra-High-Energy Density (UHED) matter in the laboratory is a challenge. Recent developments in the fabrication of vertically aligned nanowire array targets, in coordination with ultra-high-contrast femtosecond laser pulses focused to relativistic intensity, have …
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High Energy Laser Driven Electron Acceleration
An investigation was carried out looking into the process of laser wakefield acceleration of electrons, for the possible application to the generation of multi-MeV γ-rays via nonlinear Thomson scattering. The effects of introducing a gas density gradient just after the accelerating gas cell was …
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Nonlinear Evolution of Mirror Instability in the Earth's Magnetosheath in PIC Simulations
<p>Mirror modes are large amplitude non-propagating structures frequently observed in the magnetosheath and they are generated in space plasma environments with proton temperature anisotropy of larger than one. The proton temperature anisotropy also drives the proton cyclotron instability which has …
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Space-Charge Saturation and Current Limits in Cylindrical Drift Tubes and Planar Sheaths
Space-charge effects play a dominant role in many areas of physics. In high-power microwave devices using high-current, relativistic electron beams, it places a limit on the amount of radiation a device can produce. Because the beam's space-charge can actually reflect a portion of the beam, the …
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Artificial engineered materials for novel accelerator applications
… comprises of sheets of Complementary Split Ring Resonators (CSRRs). These CSRRs act as a left handed medium at certain frequencies allowing the structure to be used for the generation of reverse Cherenkov radiation. The proposed initial design exhibits a left handed TM31-like mode at 5.5 GHz …
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Dynamics of an Electrodynamic Tether System in a Varying Space-Plasma Environment
… have a wide range of proposed applications in the fields of satellite propulsion and space plasma research. The fundamental purpose of this dissertation is to improve the understanding of the behavior of an electrodynamic tether (EDT) system in Earth's ionosphere. An electrodynamic tether …
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Second Harmonic Generation Stimulated Electromagnetic Emissions during High Power High Frequency Radio Wave Interaction with the Ionosphere
The interaction of a high power, high frequency (HF) pump/electromagnetic (EM) wave transmitted from a ground-based station with the ionosphere, experiments which have been termed "ionospheric heating", produces secondary radiation known as stimulated electromagnetic emissions (SEEs). SEEs have …
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Precision electron flow measurements in a disk transmission line
In large z-pinch drivers, it is ideal to minimize the electron flow near the load while maintaining a low inductance as to not suffer a decrease in system efficiency. While inductance and electron flow are normally competing requirements, transmission lines with a spatially varying gap in the …
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Effects of Laser Frequency and Multiple Beams on Hot Electron Generation in Fast Ignition
Inertial confinement fusion (ICF) is one approach to harnessing fusion power for the purpose of energy production in which a small deuterium-tritium capsule is imploded to about a thousand times solid density with ultra-intense lasers. In the fast ignition (FI) scheme, a picosecond petawatt laser …
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SUPPRESSION OF ELECTRON THERMAL CONDUCTION IN THE HIGH β INTRACLUSTER MEDIUM OF GALAXY CLUSTERS
Understanding the thermodynamic state of the hot intracluster medium (ICM) in a galaxy cluster requires a knowledge of the plasma transport processes, especially thermal conduction. The basic physics of thermal conduction in plasmas with ICM-like conditions has yet to be elucidated, however. We use …
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Intra-pulse dynamics of laser-driven ion acceleration in ultra-thin foils
This thesis reports on experimental and numerical investigations of ion acceler-ation driven by the interaction of short, intense laser pulses with ultra-thin, solid targets in which relativistic transparency is induced. In particular, it explores the multiple laser-ion acceleration mechanisms that …
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Multiscale numerical simulations of the magnetized plasma sheath with massively parallel electrostatic particle-in-cell code
Understanding the physics of the plasma boundary and plasma-surface interactions is one of the key scientific challenges in fusion science and engineering. Large-scale integrated simulations and high-performance computing can provide valuable insights on the dynamic phenomena involved at the …
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