On the possibility of current drive in tokamaks by Bernstein modes

Current drive in a tokamak by electrostatic electron Bernstein waves is investigated. It is shown that a sufficiently large refractive index of these waves may result in regimes of rf power dissipation in which the effect of electron trapping into "banana" orbits will be essentially diminished. Besides, a stronger (as compared with O- and X-modes) absorption of electrostatic electron Bernstein modes results in an rf power input into more energetic electrons which is also favourable for the increase of the current drive efficiency.