Experimental test of quasilinear theory

Journal Article · Tue Oct 01 04:00:00 EDT 1991 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.859911· OSTI ID:5242027

Tsunoda, S I; Doveil, F; Malmberg, J H ^[1]

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1. Department of Physics, University of California, San Diego, La Jolla, California (USA)

The use of the random phase approximation in quasilinear theory has been controversial for some time. For the bump-on-tail instability this approximation leads to the neglect of mode coupling effects mediated by the resonant particles. Recently, it has been argued theoretically and numerically that resonant particle mediated mode coupling effects actually play an important role, and that the statistically averaged effect of this mode coupling is a zeroth-order increase in the growth rate. The quasilinear theory of the interaction between a warm beam and a slow wave structure is formally identical to the quasilinear theory of the interaction between a warm beam and a plasma in the weak beam limit. Strong mode coupling effects have been experimentally observed when a weak warm beam interacts with waves on a slow wave structure. When a statistical average is done over the mode coupling, however, the predicted zeroth-order increase in the growth rate is not observed.

• OSTI ID: 5242027
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 3:10; ISSN 0899-8221; ISSN PFBPE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
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BEAM-PLASMA SYSTEMS
BUMP-IN-TAIL INSTABILITY
COUPLING
INSTABILITY
INSTABILITY GROWTH RATES
OSCILLATION MODES
PLASMA
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
RANDOM PHASE APPROXIMATION
RESONANCE
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