Line-tying of interchange modes in a hot electron plasma

Journal Article · Tue Jul 01 04:00:00 EDT 1986 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.865560· OSTI ID:5791775

Gerver, M J; Lane, B G

The dispersion relation of low-frequency (..omega..<<..omega../sub c/i) electrostatic flute-like interchange modes in a mirror cell with a fraction ..cap alpha.. of hot bi-Maxwellian electrons, with bulk line-tying to cold (nonemitting) end walls, has been solved using a slab model and the local approximation. In the absence of line-tying, hot-electron interchange modes are never completely stabilized (in contrast to the conventional theory (Phys. Fluids 9, 820 (1966); Phys. Fluids 19, 1255 (1976)), which assumes monoenergetic hot electrons and has little relevance to real plasmas). In the presence of line-tying, hot-electron interchange modes are more effectively stabilized than magnetohydrodynamic (MHD) interchange modes, because (1) the line-tying is enhanced by a factor of (..omega../..nu../sub e/)/sup 1//sup ///sup 2/ when the wave frequency ..omega.. is greater than the cold-electron collision frequency ..nu../sub e/; and (2) hot-electron interchange modes can be completely stabilized, rather than merely having their growth rates reduced, if there is a spread of hot-electron-curvature drift velocities. Predictions of the minimum ..cap alpha.. needed for instability and of the first azimuthal mode number m to go unstable, and of the scaling of these quantities with neutral gas pressure, are in good quantitative agreement with observations of hot-electron interchange instabilities in the Tara tendem mirror experiment (Bull. Am. Phys. Soc. 30, 1581 (1985)), provided a correction is made for the fact that the modes in Tara are not flute-like, but should have higher amplitudes in the plug than in the central cell.

• Research Organization: Massachusetts Institute of Technology, Plasma Fusion Center, Cambridge, Massachusetts 02130
• OSTI ID: 5791775
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 29:7; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
COLD PLASMA
COLLISIONAL PLASMA
DISPERSION RELATIONS
ELECTRONS
ELECTROSTATICS
ELEMENTARY PARTICLES
FERMIONS
FLUTE INSTABILITY
HOT PLASMA
INSTABILITY
LEPTONS
MAGNETIC MIRRORS
OPEN PLASMA DEVICES
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
STABILIZATION
TANDEM MIRRORS
THERMONUCLEAR DEVICES
WALLS