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in subjects: "Plasma Macroinstabilities"  
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Pattern formation by shock processes

Description: Shock waves in condensed media often produce and leave behind periodic patterns and textures. These patterns have been observed both in real time and in postmortem examination. In many cases the patterns can be related to analogous Pattern-forming mechanisms in classical fluid dynamics, such as the Rayleigh-Taylor and Helmholtz instabilities. In other cases, the textures arise from peculiarities in the dynamic stress state immediately behind the leading edge of the shock wave. Periodic waves in… more
Date: January 1, 1983
Creator: Shaner, J.W.
Partner: UNT Libraries Government Documents Department
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3-D resistive MHD calculations for tokamak plasmas: beyond the simple reduced set of equations

Description: Numerical studies of the resistive stability of tokamak plasmas in cylindrical geometry have been performed using: (1) the full set of resistive Magnetohydrodynamic (MHD) equations and (2) an extended version of the reduced set of resistive MHD equations including diamagnetic and electron temperature effects. In particular, the nonlinear interaction of tearing modes of many helicities has been investigated. The numerical results confirm many of the features uncovered previously using the simple… more
Date: January 1, 1983
Creator: Carreras, B. A.; Garcia, L.; Hender, T. C.; Hicks, H. R.; Holmes, J. A.; Lynch, V. E. et al.
Partner: UNT Libraries Government Documents Department
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Reconnection in tokamaks

Description: Calculations with several different computer codes based on the resistive MHD equations have shown that (m = 1, n = 1) tearing modes in tokamak plasmas grow by magnetic reconnection. The observable behavior predicted by the codes has been confirmed in detail from the waveforms of signals from x-ray detectors and recently by x-ray tomographic imaging.
Date: January 1, 1983
Creator: Pare, V.K.
Partner: UNT Libraries Government Documents Department
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Review of radio-frequency, nonlinear effects on the ionosphere

Description: Modification of the ionosphere by high power radio waves in the megahertz band has been intensively investigated over the past two decades. This research has yielded advances in aeronomy, geophysics, and plasma physics with applications to radio communication and has provided a fruitful interaction of radio theorists and experimentalists. There being almost no linear effects of powerful radio waves on the ionosphere, we concentrate on the nonlinear effects. To put the subject in perspective we … more
Date: January 1, 1983
Creator: Gordon, W.E. & Duncan, L.M.
Partner: UNT Libraries Government Documents Department
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Summary of the MARS tandem-mirror reactor design

Description: A recently completed two-year study of a commercial tandem-mirror reactor design (Mirror Advanced Reactor Study (MARS)) is briefly reviewed. The end plugs are designed for trapped-particle stability, MHD ballooning, balanced geodesic curvature, and small radial electric fields in the central cell. New technologies such as lithium-lead blankets, 24 T hybrid coils, gridless direct converters and plasma halo vacuum pumps are highlighted. General characteristics of the MARS tandem mirror and STARFI… more
Date: September 1, 1983
Creator: Logan, B. G.
Partner: UNT Libraries Government Documents Department
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Fluctuations in three Los Alamos experiments

Description: We review results from three magnetic fusion experiments at Los Alamos: the ZT-40M, a reversed-field toroidal pinch; the CTX, a spheromak produced by a magnetized coaxial source; and the FRX-C, a field-reversed configuration generated by theta-pinch techniques. These experiments share the common feature that a major fraction of the confining magnetic field is associated with currents carried by the plasma. We emphasize here the important role that fluctuations play in the maintenance and evolut… more
Date: January 1, 1983
Creator: Wright, B.L.
Partner: UNT Libraries Government Documents Department
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High-density Z-pinch research

Description: The linear Z pinch is a plasma configuration which in its simplest form requires no auxiliary magnetic field; an axial current carried by the plasma produces an azimuthal confining field and provides ohmic (resistive) or implosion heating. The Lawson criterion (n tau > 10/sup 20/ m/sup -3/s) and high temperatures (T > 10 keV) must be simultaneously satisfied in any reactor scheme. Early Z-pinch experiments concentrated on the sub-atmospheric fill pressure regime, with 10/sup 19/ m/sup -3/ < n <… more
Date: January 1, 1983
Creator: Shlachter, J.S.
Partner: UNT Libraries Government Documents Department
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Creating unstable velocity-space distributions with barium injections

Description: Large Debye lengths relative to detector dimensions and the absence of confining walls makes space an attractive laboratory for studying fundamental theories of plasma instabilities. However, natural space plasmas are rarely found displaced from equilibrium enough to permit isolation and diagnosis of the controlling parameters and driving conditions. Furthermore, any plasma or field response to the departure from equilibrium can be masked by noise in the natural system. Active experiments provi… more
Date: January 1, 1983
Creator: Pongratz, M.B.
Partner: UNT Libraries Government Documents Department
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Scaling of laser-plasma interactions with laser wavelength and plasma size

Description: Plasma size is an important parameter in wavelength-scaling experiments because it determines both the threshold and potential gain for a variety of laser-plasma instabilities. Most experiments to date have of necessity produced relatively small plasmas, due to laser energy and pulse-length limitations. We have discussed in detail three recent Livermore experiments which had large enough plasmas that some instability thresholds were exceeded or approached. Our evidence for Raman scatter, filame… more
Date: January 25, 1983
Creator: Max, C. E.; Campbell, E. M.; Mead, W. C.; Kruer, W. L.; Phillion, D. W.; Turner, R. E. et al.
Partner: UNT Libraries Government Documents Department
open access

Observations of parametric instabilities in long-scalelength plasmas

Description: This paper is organized in the following manner. In the second section we discussed absorption; the dependence of scattered light signatures of parametric instabilities occurring at n/sub e/ less than or equal to n/sub c//4 on corona size is shown in section three; and evidence for suprathermal electron production in these long-scale length plasmas is presented in section four. The results and conclusions are finally summarized in section five.
Date: March 22, 1983
Creator: Campbell, E. M.; Max, C. E.; Phillion, D. W.; Turner, R. E.; Estabrooke, K.; Laskinski, B. et al.
Partner: UNT Libraries Government Documents Department
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