Exploration of new mode of operation for the device beyond the ITER in KSTAR

Abstract

The success of ITER may warrant a construction of DEMO for electric power demonstration. The complex internal control systems required for instabilities control in H-mode operation in ITER may not be possible in DEMO. In KSTAR, a scenario of stable ITB mode with a low edge q is explored as an alternative of the H-mode for the devices beyond ITER. Here, the stability boundary of the new mode and a path to optimize the ITB boundary for optimum bootstrap current are discussed. The required control tools for the remaining instabilities like sawtooth are also addressed. This includes control of the crash time of sawtooth instability with ECH and size of the q=1 surface with the off-axis current drive system. The sawtooth instability can be used for particle exhaust and confinement control.