Tandem-mirror trapped-particle modes at arbitrary collisionality

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

DOI:https://doi.org/10.1063/1.865674· OSTI ID:5955560

Cohen, R H; Nevins, W M; Berk, H L

Tandem-mirror trapped-particle modes are studied in a model system consisting of two connected square wells representing the solenoid and the end cells. Collisions are described by a Lorentz operator. A dispersion relation that is valid for arbitrary ..nu../..omega.. (..omega.. = wave frequency, ..nu.. = collision frequency) is derived. Four limits are investigated. When epsilonequivalent..nu..R/sub am//..omega.. <<1+p/sub i//p/sub e/, where R/sub am/ is the mirror ratio separating electrons trapped in the anchor from those passing to the solenoid and p/sub e/ and p/sub i/ are the fractions of passing electrons and ions, collisions destabilize a trapped-particle mode that is stable in the collisionless limit; the growth rate is proportional to epsilon/sup 1//sup ///sup 2/ for epsilon<<1 and epsilon/ln epsilon for 1+p/sub i//p/sub e/ >>epsilon>>1. When epsilon >>1+p/sub i//p/sub e/, the trapped-particle mode becomes a weakly growing drift wave with growth rate proportional to epsilon/sup -1/ ln epsilon for ..nu../..omega..<<1 and ..nu../sup -1/ for ..nu../..omega..>>1; additionally identified are two flute modes, one of which is unstable for some parameters, and a strongly damped high-frequency mode.

• Research Organization: Lawrence Livermore National Laboratory, University of California, Livermore, California 94550
• OSTI ID: 5955560
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 29:5; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
COLLISIONAL PLASMA
COULOMB FIELD
DISPERSION RELATIONS
DISTRIBUTION FUNCTIONS
DISTURBANCES
ELECTRIC FIELDS
EQUATIONS
FUNCTIONS
INSTABILITY
KINETIC EQUATIONS
LEGENDRE POLYNOMIALS
MAGNETIC MIRRORS
OPEN PLASMA DEVICES
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
POLYNOMIALS
TANDEM MIRRORS
THERMONUCLEAR DEVICES
TRAPPED-PARTICLE INSTABILITY