Spectral broadening of lower-hybrid waves by time-dependent density fluctuations

Journal Article · Thu Sep 01 04:00:00 EDT 1983 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.864444· OSTI ID:5634681

Andrews, P L; Perkins, F W

Lower-hybrid waves injected into tokamaks are scattered by turbulent time-dependent drift-wave density fluctuations. This scattering process gives rise to frequency shifts as well as angular deviations. In tokamaks, most of the frequency spreading occurs in a regime where the angular scattering results from multiple scattering events, each event having a small mean-square scattering angle. A radiative transport equation governing diffusion in both angle and frequency is derived. The solution is obtained in slab geometry via separation of variables and leads to a Mathieu equation. In the limit where the slab thickness l exceeds the typical distance for diffusion through a large angle l/sub s/, an explicit generalization of the diffusion solution to the radiative transfer equation is formed. This solution gives the combined angular and frequency spectrum in the scattering layer. In the thick slab limit, the rms frequency width of lower-hybrid waves emerging from the layer is given by ..delta omega.. = (..omega../sub d// xi/sub 0/rho/sub i/) N/sub parallel/ ((M/sub i//m/sub e/)..beta../sub i/)/sup 1/2/ (l/l/sub s/), where ..omega../sub d/ and xi/sup -1//sub 0/ are the characteristic angular frequency and correlation length of the drift-wave turbulence.

• Research Organization: Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08544
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 5634681
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 26:9; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700108* -- Fusion Energy-- Plasma Research-- Wave Phenomena
CLOSED PLASMA DEVICES
DRIFT INSTABILITY
EQUATIONS
FLUCTUATIONS
HEATING
HIGH-FREQUENCY HEATING
INSTABILITY
KINETIC EQUATIONS
LINE BROADENING
LOWER HYBRID HEATING
PLASMA
PLASMA DENSITY
PLASMA HEATING
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
PLASMA WAVES
SCATTERING
THERMONUCLEAR DEVICES
TIME DEPENDENCE
TOKAMAK DEVICES
TURBULENCE
VARIATIONS