Electron heating by mode-converted ion-Bernstein waves in ICRF heating of tokamak plasmas

Conference · Fri May 01 04:00:00 EDT 1987

OSTI ID:6193945

Ram, A K; Bers, A

In a tokamak plasma, ion-Bernstein waves (IBW) can be excited by mode-conversion of the externally launched fast wave for ICRF heating. This conversion process is known to be efficient for low k/sub parallel/'s which carry substantial power from a single loop antenna. A detailed numerical analysis of the propagation of the IBW shows that the initial small k/sub parallel/ are significantly enhanced along the rays due to toroidal effects. The upshift can occur for short radial distances of propagation and is large enough so that the IBW can Landau damp onto the electrons. This could help explain the observed strong electron heating by ICRF waves in tokamak plasmas. The numerical ray trajectory analysis is done in toroidal geometry for a hot Maxwellian plasma with gradients in temperature, density, toroidal and poloidal magnetic fields included in a WKB sense. A simple analytical model is derived which explains the upshift in k/sub parallel/ and gives results very close to the numerically obtained values. Approximate analytical conditions for appreciable electron Landau damping of the IBW are also given.

• Research Organization: Massachusetts Inst. of Tech., Cambridge (USA). Plasma Fusion Center
• DOE Contract Number: AC02-78ET51013
• OSTI ID: 6193945
• Report Number(s): DOE/ET/51013-220; PFC/CP-87-8; CONF-870570-17; ON: DE87011035
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101* -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
700108 -- Fusion Energy-- Plasma Research-- Wave Phenomena
BERNSTEIN MODE
DAMPING
ELECTRON TEMPERATURE
HEATING
HIGH-FREQUENCY HEATING
ICR HEATING
LANDAU DAMPING
MATHEMATICAL MODELS
MATHEMATICS
NUMERICAL ANALYSIS
OSCILLATION MODES
PLASMA HEATING
PRESSURE GRADIENTS
TEMPERATURE GRADIENTS
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS
WAVE PROPAGATION