Influence of energy and axial momentum spreads on the cyclotron maser instability in intense hollow electron beams

Journal Article · Sat Sep 01 04:00:00 EDT 1979 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.862785· OSTI ID:6044514

Uhm, H S; Davidson, R C

The influence of energy and axial momentum spreads on the cyclotron maser instability in an intense hollow electron beam propagating parallel to a uniform axial magnetic field B/sub 0/e/sub z/ is investigated. The stability analysis is carried out within the framework of the linearized Vlasov--Maxwell equations. It is assumed that ..nu../gamma-circumflexvery-much-less-than1, where ..nu.. is Budker's parameter and gamma-circumflexmc/sup 2/ is the characteristic electron energy. Stability properties are investigated for the choice of electron distribution function in which all electrons have a step-function distribution in energy (H=..gamma..mc/sup 2/) and a step-function distribution in axial momentum (p/sub z/). The instability growth rate is calculated including the important stabilizing influence of energy spread (epsilon=..delta gamma..) and axial momentum spread (..delta..=..delta..p/sub z/). It is shown that a modest energy spread (epsilonapprox. = a few percent) is sufficient to stabilize perturbations with high magnetic harmonic number (s> or =2). Moreover, a relatively small axial momentum spread (..delta../mcapprox. =0.1) can easily stabilize perturbations with axial wavenumber satisfying vertical-barkc/..omega../sub c/vertical-bar> or approx. =0.2, for typical beam parameters of experimental interest.

• Research Organization: Naval Surface Weapons Center, White Oak, Silver Spring, Maryland 20910
• OSTI ID: 6044514
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 22:9; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700107* -- Fusion Energy-- Plasma Research-- Instabilities
ANALYTICAL SOLUTION
BEAMS
BOLTZMANN-VLASOV EQUATION
CYCLOTRON INSTABILITY
DIFFERENTIAL EQUATIONS
DISPERSION RELATIONS
DISTRIBUTION FUNCTIONS
ELECTRON BEAMS
ENERGY RANGE
ENERGY SPECTRA
EQUATIONS
INSTABILITY
LEPTON BEAMS
MAGNETIC FIELDS
MAXWELL EQUATIONS
MOTION
NORMAL-MODE ANALYSIS
NUMERICAL SOLUTION
PARTICLE BEAMS
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
RELATIVISTIC RANGE
ROTATION
SPECTRA