Initial equilibrium for PB study for the KSTAR discharge 7328

Based on I have created an initial equilibrium for the PB studies. In addition to the information in the Minwoo’s post, I have also used some information from our e-mail correspondence. In particular, I have set the line average density as 3.6times10^{19} m^{-3} and the central electron temperature as 1.3 keV. I have also made the following assumptions:

  • The pedestal width is the same for the temperature and density profiles. It is equal to 0.06 of the normalized poloidal flux;
  • The pedestal temperature is 400 eV;
  • The pedestal density is 2.6times 10^{19} m^{-3} ;
  • The ion temperature is equal to the electron temperature;
  • I assumed that the central q is slightly above unity.

I have also used relatively standard geometry parameters for KSTAR such as the major radius is 1.77 m, the minor radius is 0.47 m, elongation is 1.9, and triangularity is 0.8.

The q95 value that I am getting using the above settings is 5.06. The plasma pressure and q profiles are shown below.

pres q

Minwoo indicated that they observed the ELM mode structures around 222~223 (cm) in major radius. In the equilibrium that I have generated the H-mode pedestal extends from R=221.8 cm to 224 cm. The location of maximum pressure gradient in my equilibrium is at R=223 cm.I think these settings are consistent with your experimental observations.

PB diagram of KSTAR discharge

Target KSTAR discharge is #7328 since we have clear ECEI observation data and toroidal mode analysis data from toroidal Mirnov coil array and toroidally separated two ECEI system.

At the current flat top, plasma current, Ip, is 750 (kA), toroidal magnetic field, BT, is 2.25 (T), safety factor at 95% poloidal flux, q95, is ~ 5 and the plasma is heated by ~3 (MW) neutral beam only.

At first, bootstrap current is calculated using Sauter’s formula.