Radio Frequency heating and current drive – Status and prospects for the Next Step

Abstract

Additional heating is a necessary requirement on all tokamaks and stellarators. All the major devices are now equipped with large additional RF heating systems and the actual data base both on the physics aspects and on the technical aspects is large and still expanding [ 1 , 2 ]. Radio Frequency techniques in the Ion Cyclotron (ICR), Lower Hybrid (LH) and Electron Cyclotron (ECR) range of frequency have proved to be very effective for one or more of their potential applications: heating, profile control, bulk current drive, non-inductive current ramp up and plasma initiation and are planned to be used on the Next Step facility. Although other RF methods are being developed, such as Ion Bernstein wave heating and current drive and Alfvén wave heating, we will restrict the discussion to the most promising and well documented methods. The corresponding main results to date and some of the relevant physics basis will be discussed first. The technical status of coupling structures, transmission lines and generators will then be given. RF techniques cover a large domain both in the physics and in the technical aspects, and consequently only highlights of the different methods will briefly be indicated.