Numerical analysis on neutral beam injection scenario for advanced tokamak operation of KSTAR tokamak

Abstract

Summary form only given, as follows. Numerical analysis has been carried out to find an optimum neutral beam injection (NBI) scenario for the advanced tokamak(AT) operation of the KSTAR tokamak using the ASTRA 1.5-D transport code and the modified analytic NBI module. The NBI module is developed on the basis of the semi-analytic theory, which involves the first orbit effects, arbitrary geometry and steady-state Fokker-Planck solution. And the model developed is used for calculating auxiliary plasma heating, non-inductive current drive and toroidal momentum source. The plasma density and temperature profiles are calculated by the ASTRA transport code self-consistently coupled with the developed NBI module In addition, toroidal rotation profiles are obtained by solving a 1-D momentum balance equation averaged over the flux surface with the assumption of anomalous transport of toroidal angular momentum. As a result of numerical simulations, time evolutions of plasma density, temperature and toroidal rotation profiles are presented for the various NBI scenarios. Calculation results indicate that the AT operation modes with a high beta, high H factor and high bootstrap current could be attained by the localized NBI control of plasma heating, current and toroidal rotation profiles in the KSTAR tokamak.