IEEE International Conference on Plasma Science (ICOPS)
IEEE 1989 International Conference on Plasma Science
DOI: 10.1109/PLASMA.1989
22-24 May 1989
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A critical review based on experiments of the self-consistent modelling leading to the power balance equation of surface waves produced plasmas
Publication Year: 1989,Page:34
Summary form only given, as follows. The authors have been conducting an extensive experimental study on one of the key parameters of high-frequency discharges, theta , which represents the average power dissipated to maintain an electron-ion pair. A self-consistent model (coupling the wave and plasma equations) can be used to predict the observed behavior of theta , especially in regard to whethe...Show More
High power microwave generation and particle accelerators
Publication Year: 1989,Page:34
Cited by: Papers (1)
Summary form only given, as follows. Some recent advances in ultra-high-power microwave generation and in the drivers for the microwave sources were reviewed. The relevance of pulse power to microwave generation was emphasized, and the constraints placed on the source by the accelerator requirements were indicated. Other pulse power driven accelerator technologies were briefly discussed.<>Show More
Summary form only given, as follows. The formation of a stead-state electric double layer (DL) in the plasma volume inside the intergrid space of a Franck-Hertz tube has been modeled theoretically. The experimental data were accounted for by a collisionless approach involving cold beams of electrons and positive ions, and low-energy particles trapped by the potential structure. This gives rise to ...Show More
Laboratory model of wave/current wings launched by rapidly moving conductors in magnetoplasmas
Publication Year: 1989,Page:35
Summary form only given, as follows. The current system set up by charged conductors moving rapidly through a magnetized plasma across B/sub 0/ has been investigated. Classical theoretical models predict that the current collected/emitted by a moving electrode will flow along a winglike structure due to the combined motion of the electrode across B/sub 0/ and the current propagation along B/sub 0/...Show More
Modified electron-acoustic and lower-hybrid drift dissipative instability in a two-electron temperature plasma
Publication Year: 1989,Page(s):35 - 36
Summary form only given, as follows. The author has considered a plasma model in which the electrons consist of two distinct groups, i.e. hot and cold. He has investigated analytically the drift dissipative instabilities of modified electron-acoustic and lower-hybrid waves in such a two-electron-temperature plasma. He has found that the modified electron-acoustic drift dissipative mode are strong...Show More
Summary form only given, as follows. The authors have obtained a steady-state plasma with the plasma frequency in the visible. Thus, in principle, phenomena such as the production of electron plasma oscillations can be observed visually. The authors have shown that metallic cesium has both a very low value of free electron density, n, due to its bloated atomic size, and a large number of bound el...Show More
On the so-called first-order magnetic pumping by sawtooth-waveform magnetic variations
Publication Year: 1989,Page:36
Summary form only given, as follows. The heating of plasmas by sawtooth-waveform magnetic-induction variations has been examined. Analytic solutions to the magnetic-pumping problem, numerical solutions to a pair of coupled partial differential equations that describe magnetic pumping, and computer simulations of magnetically pumped plasmas were used. The sawtooth variations are divided into adiab...Show More
Summary form only given, as follows. Strong oscillations (f/sub peak/ equivalent to 200 kHz) of plasma potential ( Delta Phi /kT/sub e/ approximately=2-4) and density ( Delta n/n approximately=0.2-0.5) have been observed in a two-electron-population plasma (f/sub pi/ approximately=1 MHz) which is expanding into vacuum along an external magnetic field (B approximately=0-50 G). During the expansion,...Show More
Summary form only given, as follows. The Vlasov-Maxwell equations in the Lorentz gauge and in the quasi-electrostatic limit have been considered on ion time scales in 4-6 dimensions (including nu ), subject to certain boundary and volume conditions. The sheath physics near a Faraday shield has been studied under this formulation. Several Faraday shield configurations, including the Perkins, TFTR, ...Show More
Effects of wall ablation on the internal structure and dynamics of a railgun plasma arc
Publication Year: 1989,Page(s):37 - 38
Cited by: Papers (1)
Summary form only given, as follows. Two kinds of simulation of a railgun plasma arc have been performed using MACH2, a two-dimensional diffusive magnetohydrodynamics code. The simulations are intended to model the arc in the plane of symmetry which intersects the rails and thus effectively model the arc in a gun with infinitely wide rails. Both sets include the effects of magnetic field convectio...Show More
Radiofrequency ionization of helium with turbulent flow-measurements versus theory
Publication Year: 1989,Page:37
Summary form only given, as follows. Computations have been made for two sets of conditions of RF discharge tests with helium flow investigated by M.E. Talaat (J. de Physique., Coll.C7, Suppl. No.7, vol.40, p.C7-165, 1979). The computation of the plasma column voltage V/sub p/ versus the current I were simplified by assuming a radial distribution of the electron particle density n. This is because...Show More
Armature formation and performance in a railgun using a two-stage light-gas gun injector
R.S. Hawke;A.R. Susoeff;J.R. Asay;C.A. Hall;C.H. Konrad;R.J. Hickman;J.L. Sauve
Publication Year: 1989,Page:38
Summary form only given, as follows. The use of a two-stage light-gas gun (2SLGG) as a preaccelerator in combination with a railgun is expected to reduce barrel ablation significantly and improve overall performance. In particular, the use of a hydrogen 2SLGG provides injection velocities of 6 to 8 km/s and a pure hydrogen environment immediately behind the projectile as it enters a railgun. To co...Show More
Summary form only given, as follows. Almost all experimental observations of plasma armatures in railguns have been made in bores less than 20 mm in diameter. A serious velocity-limiting interaction with the bore walls has been identified. The plasma radiates to the bore walls at power levels of several GW/m/sup 2/. The bore walls ablate and the ablated material enters the armature, resulting in ...Show More
Rail and insulator spectra from plasma railgun armatures
Publication Year: 1989,Page(s):38 - 39
Cited by: Papers (1)
Summary form only given, as follows. High-resolution radiation spectra of the plasma armature in a railgun have been recorded in the rail and insulator simultaneously, at the same axial location, using optical multichannel analyzers and 1-mm quartz fibers. The spectra have been obtained at approximately 6 mm and 24 mm from the leading edge of the armature, which correspond to the increasing curre...Show More
Experimental determination of plasma armature properties using RGS-II, a railgun simulator
M.C. Baker;B.D. Barrett;T.J. Pickens;W.C. Nunnally;J.E. Thompson
Publication Year: 1989,Page:39
Cited by: Papers (1)
Summary form only given, as follows. A description is given of an experimental device, RGS-II, that provides a moving plasma armature without a projectile, at current and velocity levels similar to those in railguns, by simulating the mass of the projectile with the magnetic back pressure of a muzzle-fed current pulse. This device is ideally suited for the implementation of diagnostic techniques b...Show More
Parametric studies of high-heat-flux-induced erosion of surfaces in an electrothermal accelerator
O. Hankins;M. Bourham;O. Auciello;J. Stock;J. Gilligan;B. Wehring
Publication Year: 1989,Page(s):39 - 40
Cited by: Papers (1)
Summary form only given, as follows. The plasma device called SIRENS was designed and constructed to study the phenomena occurring during the interaction of a high-heat flux with a material surface. The device works on the same principle as an electrothermal mass accelerator. A plasma is produced by the ablation of an insulating cylindrical sleeve of Lexan between two tungsten alloy electrodes. Th...Show More
Spectroscopic investigation of the RGS-II hypervelocity plasma armature
Publication Year: 1989,Page:39
Summary form only given, as follows. A spectroscopic investigation of the plasma armature in the railgun simulator RGS-II is underway. RGS-II can accelerate the plasma armature to velocities up to 20 km/s and produce armature currents up to 300 kA. The optical signal is extracted at the midbore position by a fiber-optic bundle. Emission spectra are recorded by an optical multichannel analyzer sys...Show More
Modelling of the vapor shield mechanism during high heat flux ablation of surfaces
Publication Year: 1989,Page:40
Summary form only given, as follows. The ablation process occurring at material surfaces in electromagnetic launchers, electrothermal guns, etc., which has a profound impact on device performance in the areas of projectile drag, conversion efficiency, and component lifetime, has been studied. The vapor shield mechanism that develops to form the ablation plasma boundary layer under these conditions...Show More
Plasma opening switch experiments on the Particle Beam Accelerator II
M.A. Sweeney;D.H. McDaniel;C.W. Mendel;G.E. Rochau;W.B.S. Moore;G.R. Mowrer;W.W. Simpson;D.M. Zagar;T. Grasser;C.D. McDougal
Publication Year: 1989,Page(s):40 - 41
Summary form only given, as follows. The authors have developed and tested three different plasma-opening switch (POS) designs that use magnetic fields to control and confine the injected plasma. All three configurations couple current efficiently to a 5- Omega electron beam diode. In the first switch, a plasma generated by flashboard sources is injected into the 20- Omega magnetically insulated t...Show More
Summary form only given, as follows. Two-dimensional single-fluid magnetohydrodynamic simulations have been conducted to investigate the effects of the Hall electric field on magnetic field transport in plasma opening switches of the type used on GAMBLE I. The Hall terms were included in the magnetic field transport equation in the two-dimensional simulation code MACH2 through the use of a general...Show More
Numerical and theoretical developments in plasma erosion opening switch research
Publication Year: 1989,Page:41
Summary form only given, as follows. The plasma erosion opening switch (PEOS) can conduct megaampere levels of current for 50 ns to 1 mu s before opening into a load. The opening times can be a factor of ten times smaller than the conduction times. It has been observed experimentally that the switch does not open until the magnetic field and current penetrate through to the load end of the plasma,...Show More
Characterization of a 1- mu s, 1-MA plasma erosion opening switch
R.J. Commisso;J.R. Boller;J.M. Grossmann;D.D. Hinshelwood;J.C. Kellogg;D. Mosher;P.F. Ottinger;B.V. Weber
Publication Year: 1989,Page:42
Summary form only given, as follows. Experiments have been carried out to characterize the conduction phase of the plasma erosion opening switch (PEOS) driven by a fused capacitor bank. Initial experiments with a PEOS cathode (anode) radius of 5 cm (8.9 cm) used magnetic probes to determine the PEOS current distribution and collimated, visible light detectors and Faraday cups to detect the presen...Show More
Compact pulsed power generator using fuses and plasma erosion opening switches
Publication Year: 1989,Page(s):42 - 43
Summary form only given, as follows. A compact pulsed power generator based on an inductive energy storage system has been constructed and tested. The generator, which has been named ASO-1, is about 210 cm high. Parallel fuses and plasma erosion opening switches are used as two-stage opening switches. The operation of the generator is described. It has been confirmed by experiment that the paralle...Show More
Summary form only given, as follows. The two-dimensional implicit ANTHEM code has been used to examine the feasibility of plasma opening switch operation at conduction times ranging from 500 ns to 3 mu s. The classical bicylindrical switch is examined with a cathode radius of 8 cm, an anode radius of 11.5 cm, and a plasma length of 20 cm as typical dimensions. The generator current rises linearly ...Show More
Investigation of electron and ion flows in the microsecond plasma opening switch on the terawatt power level
A.N. Bastrikov;S.P. Bugaev;V.M. Bystritskii;A.M. Volkov;S.V. Grigoriev;A.A. Kim;B.M. Koval'chuk;V.M. Kokeshenev;Y.E. Krasik;I.V. Lisitsyn;G.A. Mesyats;V.A. Yakovlev
Publication Year: 1989,Page:43
Summary form only given, as follows. The results of an investigation of ion and electron flows in a coaxial microsecond plasma opening switch (POS) are given. A 1- mu s front duration POS with outer and inner electrodes with diameters of 210 mm and 75 mm, respectively, switched a 1-MA pulse during 0.1 mu s to a 120-cm-long short-circuited coaxial line with matching diameters. The polarity of the i...Show More
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