Suppression of Rayleigh--Taylor and bulk convective instabilities in imploding plasma liners and pinches

Journal Article · Fri Jun 01 00:00:00 EDT 1990

DOI:https://doi.org/10.1063/1.859252· OSTI ID:6765206

Bud'ko, A B; Liberman, M A; Velikovich, A L ^[1]; Felber, F S ^[2]

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1. Institute for Physical Problems, Moscow 117334, U.S.S.R (SU)
2. JAYCOR, P.O. Box 85154, San Diego, CA (USA)

Linear growth of instabilities during implosion of annular and columnar plasma pinches having sharp outer boundaries is analyzed. The dominant modes of the Rayleigh--Taylor 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 Rayleigh--Taylor 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 Rayleigh--Taylor 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.

• OSTI ID: 6765206
• Resource Relation: Journal Volume: 2:6
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CONVECTIVE INSTABILITIES
INHIBITION
LINERS
PLASMA MACROINSTABILITIES
PINCH DEVICES
RAYLEIGH-TAYLOR INSTABILITY
ALIGNMENT
ANNULAR SPACE
ASPECT RATIO
EQUILIBRIUM
HYDRODYNAMICS
IMPLOSIONS
INSTABILITY GROWTH RATES
MAGNETIC FIELDS
OPTIMIZATION
SHEAR
STABILITY
STEADY-STATE CONDITIONS
THICKNESS
CONFIGURATION
DIMENSIONS
FLUID MECHANICS
INSTABILITY
MECHANICS
PLASMA INSTABILITY
SPACE
THERMONUCLEAR DEVICES
700107* - Fusion Energy- Plasma Research- Instabilities