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.
Results
Showing 1 to 20 of 44 for “"beam physics"”.
-
Quadrupole Strong Focusing for Space-Charge Dominated Electron Beams in Traveling-Wave Tubes
Analysis of quadrupole focusing lattices for high-frequency TWTs is presented. This work is motivated by recent work performed at the Naval Research Laboratory (NRL) which demonstrated an advantageous case for strong focusing employing a Halbach quadrupole lattice. Using realistic Permanent Magnet …
-
Identifying Signatures of Plasma Waves and Reconnection Associated with Kelvin-Helmholtz Activity
<p>The magnetopause marks the boundary between the shocked solar wind and magnetospheric plasma. Understanding the dynamics of the plasma processes at the magnetopause boundary is crucial to the study of plasma transport into the magnetosphere. Previous studies have shown that there exists a …
-
Whistler Waves: Modeling and Observations
<p>The thesis presents the results of all the research from the published and in publication process research in the Journal of Geophysical Research [1]. This research focuses on whistler wave ducting events in the equatorial magnetosphere. High-density ducts are the main focus of whistler study in …
-
Instrument Design Optimization with Computational Methods
… is presented with a focus on primary electron beam deflection downstream of the target. The SHMS consists of a superconducting horizontal bending magnet (HB) and three superconducting quadrupole magnets. The HB allows particles scattered at an angle of $5.5° to the beam line to be steered into …
-
Setting Constraints on the Lunar Exosphere: A Comprehensive Analysis of Velocity Resolved Sodium and Potassium Line Profile Measurements
<p>This dissertation outlines and presents the most comprehensive set of velocity-resolved measurements of sodium D2 (5889.9509 Å) lines taken over multiple lunations spanning seven years (2011 – 2017). These data are used to study the morphology and dynamics of the lunar exosphere. Additionally, …
-
Particle swarms in confining geometries
<p>The transport of micro- and nano-particles in subsurface fluid deposits is an area of increasing interest due to the rising use of these particles for consumer and industrial purposes. Subsurface particle transport is complicated by the presence of fractures and fracture networks which govern …
-
Characterization of a Magnetically Contained Hot Filament Plasma Source with a Wide-Sweeping Langmuir Probe
<p>Ionospheric plasma research in the Space and Atmospheric Instrumentation Laboratory’s Space Plasma Chamber has been hindered by the lack of a suitable plasma diagnostic instrument and understanding of its hot-filament plasma source. This thesis describes efforts made to remedy both problems. A …
-
Optical spectroscopy and langmuir probe diagnostics of microwave plasma in synthesis of graphene-based nanomaterials
<p>Along with the revolutionary discovery and development of carbon nanostructures, such as carbon nanotubes and graphitic sheets, has arrived the potential for their application in the fields of medicine, bioscience and engineering due to their exceptional structural, thermal and electrical …
-
Characterization of Argon and Ar/Cl<sub>2</sub> Plasmas Used for the Processing of Niobium Superconducting Radio-Frequency Cavities
<p>The plasma processing of superconducting radio-frequency (SRF) cavities has shown significant promise as a complementary or possible replacement for the current wet etch processes. Empirical relationships between the user-controlled external parameters and the effectiveness of Reactive Ion …
-
Langmuir Probe Instrument Suite for Mesosphere Turbulence Experiment Mission
<p>The Langmuir probe technique is the predominant in-situ plasma diagnostic technique, and is arguably the only measurement technique that is universally own on every sounding rocket investigation. Earth's mesosphere region (80-120 km) is a host of many dynamic phenomena such as the noctilucent …
-
Characterization of Microwave Discharge Plasmas for Surface Processing
<p>We have developed several diagnostic techniques to characterize two types of microwave (MW) discharge plasmas: a supersonic flowing argon MW discharge maintained in a cylindrical quartz cavity at frequency ƒ = 2.45 GHz and a pulse repetitive MW discharge in air at ƒ = 9.5 GHz. Low temperature MW …
-
Application of Chebyshev Formalism to Identify Nonlinear Magnetic Field Components in Beam Transport System
… conducted at Jefferson Lab's Continuous Electron Beam Accelerator Facility to develop a beam-based technique for characterizing the extent of the nonlinearity of the magnetic fields of a beam transport system. Horizontally and vertically oriented pairs of air-core kicker magnets were …
-
Study of Plasmonic Properties of the Gold Nanorods in the Visible to Near Infrared Light Regime
<p>Nanostructures of noble metals show unique plasmonic behavior in the visible to near-infrared light range. Gold nanostructures exhibit a particularly strong plasmonic response for these wavelengths of light. In this study we have investigated optical enhancement and absorption of gold nanorods …
-
A 3-D Model of the Auroral Ionosphere
<p>A new 3-D model of the high latitude ionosphere is developed to study the coupling of the ionosphere with the magnetosphere and neutral atmosphere. The model consists of equations describing conservations of mass, momentum and energy for the six ionospheric constituents (O+, NO+, N+2 , O+2 , N+ …
-
Integrated broadband microphotonic beamformer for adaptive nulling in smart antennas
… arrays capable of adaptively adjusting the beam pattern, thereby enhancing the desired signals (beam steering) and suppressing the interference signals (null steering), which is also known as Space Division Multiple Access (SDMA). SDMA systems allow significant improvement in the area of …
-
Large-Angle Beamstrahlung: Simulation And Diagnostics
<p>LARGE-ANGLE BEAMSTRAHLUNG: SIMULATION AND DIAGNOSTICS</p> <p>by</p> <p>RYAN S. GILLARD</p> <p>May 2014</p> <p>Advisor: Dr. Giovanni Bonvicini </p> <p>Major: Physics </p> <p>Degree: Doctor of Philosophy </p> <p> Luminosity is paramount in high energy physics research, therefore it is critical to …
Page 1 of 3