Microwave heating and current drive in tokamaks

The use of powerful microwave sources provides unique opportunities for novel and efficient heating and current drive schemes in the electron cyclotron and lower hybrid ranges of frequencies. Free electron lasers and relativistic klystrons are new sources that have a number of technical advantages over conventional, lower intensity sources; their use can lead to improved current drive efficiencies and better penetration into a reactor grade plasma in specific cases. The paper reports on modelling of absorption and current drive in intense pulse and quasi-linear regimes and on analysis of parametric instabilities and self-focusing. (author). 16 refs, 2 figs, 1 tab