L. Krlin et P. Pavlo, INFLUENCE OF INDUCED DIFFUSION OF THERMONUCLEAR ALPHA-PARTICLES ON THEIR ENERGY-TRANSFER INTO LOWER-HYBRID WAVES, Nuclear fusion, 34(11), 1994, pp. 1517-1521
Recently, a new mechanism was proposed by Fisch and Rax which could le
ad to the amplification of lower hybrid (LH) waves (LHWs) at the expen
se of alpha particle energy, thus improving the LH current drive effic
iency. The method of quasi-linear lines of diffusion constraints used
in the present contribution yields a more complete description of the
above mentioned effect; the role of additional terms that are revealed
is discussed. One of the necessary prerequisites for the mechanism to
become operative is a sufficiently deep penetration of LHWs into the
plasma column. A simple numerical analysis performed shows that this c
ondition is more likely to be met in more conventional tokamaks than i
n those with a bean shaped cross-section.