Generating a new equilibrium for the KSTAR discharge 6123 simulated with the XGC0 code


I have used the TEQ code in CALTRANS to generate a new equilibrium for the case T85Y that I have simulated using the XGC0 code last week. The plasma pressure and the bootstrap current profiles in the pedestal region are updated and a new equilibrium is generated. In order to ensure that the plasma profiles are monotonic, I have introduced a transition region where the profiles are modified. The plasma pressure in the transition region is computed using the following expression:

p(psi) = p_{rm eq}(psi) + dp left(tanhleft(displaystylefrac{psi-0.83}{0.2}right)+1right),

where p_{rm eq} is the plasma pressure in the original equilibrium files that is updated with the plasma pressure p(psi), $dp$ is the gap between the equilibrium pressure p_{rm eq} and the plasma pressure found by the XGC0 code at psi=0.83. This formula is applied for psi from 0 to 0.83. The characteristic width of the transition region is set to 0.2. The bootstrap current profile is updated in the same way.

The plasma profiles after update for the cases T85Y and T87Y looks like:

Plasma profiles in the original equilibrium and updated plasma profiles for the case T85Y

Plasma profiles in the original equilibrium and updated plasma profiles for the case T85Y

Plasma profiles in the original equilibrium and updated plasma profiles for the case T87Y

Plasma profiles in the original equilibrium and updated plasma profiles for the case T87Y

There is still change in the plasma pressure gradient in the transition region for the case T87Y. The transition width might need to be increased.