Density Clamping and Power Deposition Profile in rf Heated Plasma in Toroidal Helical Systems

概要

論文の詳細を見る
Radial transport driven by rf heating in toroidal helical systems with the largehelical ripple is studied. The cyclotron resonance heating changes the pitch angle ofresonating particles, so that the transition from the transit orbit to the trapped one occurs. The deviation of the average minor radius of the particle orbit from themagnetic surface strongly depends on the pitch angle of the particle velocity. Owingto this dependence, the slight change in the pitch angle by heating can generate a largestep in the radial location. The approximate forms of the driven radial flow, which isrf-power-dependent, and the deformation of the heating profile are obtained. It isfound that the deposition profile in this configuration is hardly made sharper thana critical gradient length. The injection of the heating power from the inside ofthe torus is preferable to improve the heating efficiency and to overcome the densityclamping.
1989-02-15