2018 IEEE International Conference on Plasma Science (ICOPS), 2018
The multipactor effect is a discharge phenomenon which may occur when secondary electron emission... more The multipactor effect is a discharge phenomenon which may occur when secondary electron emission (SEE) is in resonance with an electric field under certain vacuum conditions [1]. Liberated electrons will oscillate between two surfaces driven by a radio frequency (RF) field; this discharge cultivates and sustains itself by SEE through reoccurring impacts with the surface. This can lead to deterioration of vacuum RF electronics' performance [2]. To suppress the multipactor effect, the secondary electron yield (SEY) must be reduced.
Page 1. Recent results from the National Spherical Torus Experiment This article has been downloa... more Page 1. Recent results from the National Spherical Torus Experiment This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2003 Plasma Phys. Control. Fusion 45 657 (http://iopscience.iop.org/0741-3335/45/5/310) ...
Summary form only given. The design construction and operation of two quadrature homodyne millime... more Summary form only given. The design construction and operation of two quadrature homodyne millimeter wave interferometers, one operating at 96 GHz and the second operating at 40 GHz, are described. Together with electrostatic probes, these interferometers will provide absolute electron density measurements at two axial locations in the Helcat (helicon-cathode) plasma device. Helcat is a four meter long magnetized plasma device with a thermionic cathode source at one end and a RF helicon source at the other. Plasma densities with both sources range from 1012-1014/cc, often with significant axial density gradients. The two interferometer frequencies are optimized for operation at the high and low density ends of the device respectively. The circuit, optical and mechanical design as well as initial measurements will be presented.
Research is being conducted at UNM to verify the theoretical relationship between Alfv'en wav... more Research is being conducted at UNM to verify the theoretical relationship between Alfv'en waves and neutral density in Helium plasmas. We are particularly interested in the role collisionality plays in wave damping and mode structure development. The non-axisymmetric waves are launched using a hand wound emitter coil driven by a differential current amplifier circuit. The receiver consists of a hand
Plasma guns are being developed for use on the Plasma Liner Experiment (PLX) located at LANL. The... more Plasma guns are being developed for use on the Plasma Liner Experiment (PLX) located at LANL. The collapsing plasma liner will be formed via merging of 30-60 dense, high Mach number plasma jets (n˜10^16-17 cm-3, M˜10--35, v˜50--70 km/s, rjet˜5 cm) in a spherically convergent geometry. Small parallel-plate railguns are being developed for this purpose. Each gun will operate at ˜300-600
Magnetized Liner Inertial Fusion (MagLIF) experiments, where a metal liner is imploded to compres... more Magnetized Liner Inertial Fusion (MagLIF) experiments, where a metal liner is imploded to compress a magnetized seed plasma may generate peak magnetic fields ∼10(4) T (100 Megagauss) over small volumes (∼10(-10)m(3)) at high plasma densities (∼10(28)m(-3)) on 100 ns time scales. Such conditions are extremely challenging to diagnose. We discuss the possibility of, and issues involved in, using polarimetry techniques at x-ray wavelengths to measure magnetic fields under these extreme conditions.
... Mark Gilmore (University of New Mexico). Alan Lynn (University of New Mexico). Bruno Bauer (U... more ... Mark Gilmore (University of New Mexico). Alan Lynn (University of New Mexico). Bruno Bauer (University of Nevada Reno). F. Douglas Witherspoon (HyperV Technologies Corp). Jason Cassibry (University of Alabama Huntsville). Scott Hsu (Los Alamos National Laboratory). ...
Secondary Electron Emission (SEE) results from bombarding materials with electrons, atoms, or ion... more Secondary Electron Emission (SEE) results from bombarding materials with electrons, atoms, or ions. The amount of secondary emission depends on factors such as bulk and surface properties of materials, energy of incident particles, and their angle of incidence. Total secondary electron emission yield, defined as the number of secondary electrons ejected per primary electron, is an important material parameter. Materials
2018 IEEE International Conference on Plasma Science (ICOPS), 2018
The multipactor effect is a discharge phenomenon which may occur when secondary electron emission... more The multipactor effect is a discharge phenomenon which may occur when secondary electron emission (SEE) is in resonance with an electric field under certain vacuum conditions [1]. Liberated electrons will oscillate between two surfaces driven by a radio frequency (RF) field; this discharge cultivates and sustains itself by SEE through reoccurring impacts with the surface. This can lead to deterioration of vacuum RF electronics' performance [2]. To suppress the multipactor effect, the secondary electron yield (SEY) must be reduced.
Page 1. Recent results from the National Spherical Torus Experiment This article has been downloa... more Page 1. Recent results from the National Spherical Torus Experiment This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2003 Plasma Phys. Control. Fusion 45 657 (http://iopscience.iop.org/0741-3335/45/5/310) ...
Summary form only given. The design construction and operation of two quadrature homodyne millime... more Summary form only given. The design construction and operation of two quadrature homodyne millimeter wave interferometers, one operating at 96 GHz and the second operating at 40 GHz, are described. Together with electrostatic probes, these interferometers will provide absolute electron density measurements at two axial locations in the Helcat (helicon-cathode) plasma device. Helcat is a four meter long magnetized plasma device with a thermionic cathode source at one end and a RF helicon source at the other. Plasma densities with both sources range from 1012-1014/cc, often with significant axial density gradients. The two interferometer frequencies are optimized for operation at the high and low density ends of the device respectively. The circuit, optical and mechanical design as well as initial measurements will be presented.
Research is being conducted at UNM to verify the theoretical relationship between Alfv'en wav... more Research is being conducted at UNM to verify the theoretical relationship between Alfv'en waves and neutral density in Helium plasmas. We are particularly interested in the role collisionality plays in wave damping and mode structure development. The non-axisymmetric waves are launched using a hand wound emitter coil driven by a differential current amplifier circuit. The receiver consists of a hand
Plasma guns are being developed for use on the Plasma Liner Experiment (PLX) located at LANL. The... more Plasma guns are being developed for use on the Plasma Liner Experiment (PLX) located at LANL. The collapsing plasma liner will be formed via merging of 30-60 dense, high Mach number plasma jets (n˜10^16-17 cm-3, M˜10--35, v˜50--70 km/s, rjet˜5 cm) in a spherically convergent geometry. Small parallel-plate railguns are being developed for this purpose. Each gun will operate at ˜300-600
Magnetized Liner Inertial Fusion (MagLIF) experiments, where a metal liner is imploded to compres... more Magnetized Liner Inertial Fusion (MagLIF) experiments, where a metal liner is imploded to compress a magnetized seed plasma may generate peak magnetic fields ∼10(4) T (100 Megagauss) over small volumes (∼10(-10)m(3)) at high plasma densities (∼10(28)m(-3)) on 100 ns time scales. Such conditions are extremely challenging to diagnose. We discuss the possibility of, and issues involved in, using polarimetry techniques at x-ray wavelengths to measure magnetic fields under these extreme conditions.
... Mark Gilmore (University of New Mexico). Alan Lynn (University of New Mexico). Bruno Bauer (U... more ... Mark Gilmore (University of New Mexico). Alan Lynn (University of New Mexico). Bruno Bauer (University of Nevada Reno). F. Douglas Witherspoon (HyperV Technologies Corp). Jason Cassibry (University of Alabama Huntsville). Scott Hsu (Los Alamos National Laboratory). ...
Secondary Electron Emission (SEE) results from bombarding materials with electrons, atoms, or ion... more Secondary Electron Emission (SEE) results from bombarding materials with electrons, atoms, or ions. The amount of secondary emission depends on factors such as bulk and surface properties of materials, energy of incident particles, and their angle of incidence. Total secondary electron emission yield, defined as the number of secondary electrons ejected per primary electron, is an important material parameter. Materials
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