ICRF performance in ET

Abstract

The current results on the large UCLA Electric Tokamak (ET, R=5 m, a=1 m) indicate that its potential for ICRF heating and current drive is sufficiently robust to explore plasma stability beyond the Troyon limit up to the unity beta regime. The achievement of unity beta plasmas requires virtually steady state, non-inductive plasmas with an energy confinement time of about 1 second. Due to the large volume of ET (150 m3), the Ohmic plasma confinement is excellent (a central energy confinement time of 350 msec has been achieved) and we estimate that the anomalous electronic heat conduction will not be a limiting factor for high beta exploration. In this paper we will present the current status of the ICRF experiments and the realization of excellent antenna loading using water-loaded couplers in the range of 1 to 10 MHz. The goal is to achieve unity beta plasmas by ICRF heating and current drive, relying on a large bootstrap current fraction. The reactor related aspects of this research are very exciting, provided a deep second stable plasma core can be produced by ICRF-based techniques.