Steady-state and plasma start-up operations for the ARIES-IV second-stability tokamak reactor

ARIES-IV is a conceptual steady-state tokamak power plant that relies on second-stability operation to achieve high plasma beta (3.4%) at low current drive power (71 MW). Very precise current profile alignment is required to maintain stability, making use of prescribed ICRF fast wave and lower-hybrid power spectra at 124 MHz and 8 GHz, respectively. Two plasma start-up procedures have been developed. The reference scenario involves a slow noninductive start-up along a thermally stable path in ⟨n⟩-⟨T⟩ space that permits a full range of partial power operations but requires a minimum of 130 MW of heating power. The alternative approach is a fast inductive start-up that requires 78 MW of auxiliary power and 324 V-s from the poloidal-field coils to reach full power in 3000 s