The EAST experiments have demonstrated that such technical and scientific challenges can be resolved. This was achieved in plasmas with dominant electron heating and low input torque driving the plasma current with an actively cooled ITER-like tungsten divertor with the capability to handle a heat flux of up to 10 MWm-2. EAST achieved a fully non-inductive current-driven steady-state plasma with a normalized confinement factor H89 of ~1.3 (i.e., 30% higher than L-mode confinement) and total injected energy into the plasma of 1.73 GJ (see Figure 1). In these plasmas, 70% of the current is driven by the heating and current drive systems while 30% is driven by the plasma itself due to transport processes (bootstrap current) because of the high normalized pressure of the plasma (poloidal beta ~ 1.5). For comparison, in the ITER 10 MA Q ≥ 5 steady-state plasma scenario the poloidal beta is ~ 1.0 and 66% of the current is driven by heating and current drive systems and 33% by the plasma itself (i.e., a very similar proportion to the EAST results, see Figure 2).
Figure 1. EAST's 1056-second steady-state high-temperature plasma discharge. From top to bottom: Plasma normalized pressure (poloidal beta); voltage applied by the central solenoid; electron temperature and injected energy into the plasma; plasma density; and peripheral deuterium light emission and heat flux to the divertor target.