Suppression of RayleighTaylor and bulk convective instabilities in imploding plasma liners and pinches
Abstract
Linear growth of instabilities during implosion of annular and columnar plasma pinches having sharp outer boundaries is analyzed. The dominant modes of the RayleighTaylor instability differ in time, radius, and growth rate from the dominant modes of the bulk convective instability. The spectra of growth rates of perturbations localized azimuthally or axially suggest explanations for filamentation and stratification of plasmas. Localized RayleighTaylor modes grow fastest initially in an implosion. These modes can be suppressed completely, however, by a relatively modest axial magnetic field, which produces magnetic shear in a Z pinch. Similarly, bulk convective modes can be substantially reduced by magnetic shear. The window of stability'' produced by magnetic shear occurs for an axial field magnitude about equal to the azimuthal. Properly shaped current pulses in Z pinches with axial fields may therefore produce stable implosions to high compression ratios, in agreement with recent experiments. The most dangerous RayleighTaylor modes for the symmetry of an annular pinch of initial aspect ratio {ital R}{sub 0}/{delta}{sub 0} are those with wavenumber {ital k}{similar to}{ital R}{sub 0}/{delta}{sup 2}{sub 0}, where {ital R}{sub 0} is the initial pinch radius. To suppress pinch instabilities optimally, both the liner thickness and axial magnetic field should bemore »
 Authors:

 Institute for Physical Problems, Moscow 117334, U.S.S.R (SU)
 JAYCOR, P.O. Box 85154, San Diego, CA (USA)
 Publication Date:
 OSTI Identifier:
 6765206
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Volume: 2:6
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CONVECTIVE INSTABILITIES; INHIBITION; LINERS; PLASMA MACROINSTABILITIES; PINCH DEVICES; RAYLEIGHTAYLOR INSTABILITY; ALIGNMENT; ANNULAR SPACE; ASPECT RATIO; EQUILIBRIUM; HYDRODYNAMICS; IMPLOSIONS; INSTABILITY GROWTH RATES; MAGNETIC FIELDS; OPTIMIZATION; SHEAR; STABILITY; STEADYSTATE CONDITIONS; THICKNESS; CONFIGURATION; DIMENSIONS; FLUID MECHANICS; INSTABILITY; MECHANICS; PLASMA INSTABILITY; SPACE; THERMONUCLEAR DEVICES; 700107*  Fusion Energy Plasma Research Instabilities
Citation Formats
Bud'ko, A B, Liberman, M A, Velikovich, A L, and Felber, F S. Suppression of RayleighTaylor and bulk convective instabilities in imploding plasma liners and pinches. United States: N. p., 1990.
Web. doi:10.1063/1.859252.
Bud'ko, A B, Liberman, M A, Velikovich, A L, & Felber, F S. Suppression of RayleighTaylor and bulk convective instabilities in imploding plasma liners and pinches. United States. doi:10.1063/1.859252.
Bud'ko, A B, Liberman, M A, Velikovich, A L, and Felber, F S. Fri .
"Suppression of RayleighTaylor and bulk convective instabilities in imploding plasma liners and pinches". United States. doi:10.1063/1.859252.
@article{osti_6765206,
title = {Suppression of RayleighTaylor and bulk convective instabilities in imploding plasma liners and pinches},
author = {Bud'ko, A B and Liberman, M A and Velikovich, A L and Felber, F S},
abstractNote = {Linear growth of instabilities during implosion of annular and columnar plasma pinches having sharp outer boundaries is analyzed. The dominant modes of the RayleighTaylor instability differ in time, radius, and growth rate from the dominant modes of the bulk convective instability. The spectra of growth rates of perturbations localized azimuthally or axially suggest explanations for filamentation and stratification of plasmas. Localized RayleighTaylor modes grow fastest initially in an implosion. These modes can be suppressed completely, however, by a relatively modest axial magnetic field, which produces magnetic shear in a Z pinch. Similarly, bulk convective modes can be substantially reduced by magnetic shear. The window of stability'' produced by magnetic shear occurs for an axial field magnitude about equal to the azimuthal. Properly shaped current pulses in Z pinches with axial fields may therefore produce stable implosions to high compression ratios, in agreement with recent experiments. The most dangerous RayleighTaylor modes for the symmetry of an annular pinch of initial aspect ratio {ital R}{sub 0}/{delta}{sub 0} are those with wavenumber {ital k}{similar to}{ital R}{sub 0}/{delta}{sup 2}{sub 0}, where {ital R}{sub 0} is the initial pinch radius. To suppress pinch instabilities optimally, both the liner thickness and axial magnetic field should be chosen properly.},
doi = {10.1063/1.859252},
journal = {},
issn = {08998221},
number = ,
volume = 2:6,
place = {United States},
year = {1990},
month = {6}
}