Quasi-linear theory of Cerenkov plasma heating

• Published in: Nuclear fusion 1967-12, Vol.7 (4), p.177-184
• Main Authors: Dolgopolov, V.V, Sizonenko, V.L
• Format: Article
• Language: English
• ISSN: 0029-5515; 1741-4326
• DOI: 10.1088/0029-5515/7/4/001

The authors investigate Cerenkov heating in a radially non-uniform plasma cylinder, taking into account the effect of oscillations on the ‘background’ charged particle distribution function. They derive equations for particle diffusion in velocity space which are valid for both ‘narrow’ and ‘broad’ wave packets, and also expressions for the energy absorbed by the plasma. The effect of collisions is taken into account. The energy gained per unit time by an ion is estimated for the case of ‘broad’ wave packets, when the ‘background’ distribution function is non-Maxwellian to an insignificant extent. It is shown that in the case of ‘narrow’ wave packets, when the coefficient of diffusion in velocity space (characterizing the effect of oscillations on the ‘background’ distribution function) exceeds the coefficient of diffusion due to collisions, ‘absorption saturation’ ensues and an increase in the amplitude of the electromagnetic field does not lead to an increase in absorbed energy. It is also shown that heating with ‘narrow’ wave packets is no less effective than heating with ‘broad’ wave packets, provided that the ‘background’ distribution function in the latter case is not significantly non-Maxwellian.