ANTENNA SPECTRUM EFFECTS ON THE EFFICIENCY OF ALVEN WAVE EXCITATION
In the FIVA device, the MHD waves are excited in the omega/omega-ci<1 frequency range. The parameter range of the device (B-o =0.3 tesla, n-o =10**21m**-3) allows for the simultaneous excitation of the resonant magnetoacoustic (M.A.) modes as well as the localized Alfven waves. The experiments at the moderate excitation levels, with the full turn and sector antenna, were performed. It is observed that, the sector antenna excites the Alfven layers more efficiently than the symmetric full turn loop. In the case of the symmetric excitation the coupling between the M.A. and Alfven waves relies on the Hall electric field while in the case of the sector loop the coupling is due to the non-symmetry of the exciting field. The additional case of coupling is provided by the shear in the static magnetic field which enhances the effect of the Hall electric field for the symmetrically excited wave. The M.A. cavity modes are efficiently damped by the localized Alfven waves.
Bibliographic Reference: 4TH INTERNATIONAL SYMPOSIUM ON HEATING IN TOROIDAL PLASMAS, ROMA (ITALY), MARCH 21-28, 1984 VOL. I, PP. 165- 170 1478 P., VOL. I AND VOL. II, 1984 WRITE TO MONOTYPIA FRANCHI, ST. LUCIA + VIALE UMBRIA NO. 28, 06012 CITTA DI CASTELLO, PERUGIA (ITALY), USD 6
Record Number: 1989124024800 / Last updated on: 1987-01-01
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