Simulations to test different smoothing algorithms are submitted on FRANKLIN

Two new cases are submitted on FRANKLIN in order to investigate different settings for smoothing.

  • Case XGC-208 is based on the case XGC-206, except of fm_nsmooth_chi that is increased from 1 to 2.
  • Case XGC-209 is submitted to test new procedure to smooth the radial electric field profiles. In addition to the parameter fm_nsmooth that is kept 1 (as in the previous cases), the following settings are used:

fm_nsmooth_er = 4 ! number of smoothing for radial electric field in the core refion
fm_smooth_er_rhob = 0.95 ! rho where transition between different level of smoothing is applied
fm_smooth_er_coef = 75. ! coefficient that controls sharpness of transition between different level of smoothness for Er
fm_nsmooth_chi = 2 ! number of applications of diffusivity smoothing in fmcfm_call


New smoothing procedure for radial electric field is implemented

New procedure for smoothing of radial electric field profile is implemented in the fmcfm_call routine. Different levels of smoothing is applied in the plasma core and in the plasma edge. The radial electric field profile in the plasma edge is smoothed fm_nsmooth times together other plasma profiles such as electron and ion temperatures and plasma density profiles. The radial electric field in the plasma core is smoothed fm_nsmooth_er times. The new smoothed profiles are merge together using the following formula:

{Huge E_r} = displaystylefrac{1}{2} left[ E_r^{rm core} left( 1 - tanh(C_{er} (rho-rho_b)) ) + E_r^{rm edge} ( 1 + tanh(C_{er} (rho-rho_b)) right) right]

and used in the computation of the ExB flow shear. Here, C_{er} is the coefficient that describes sharpness of the transition between two smoothed profiles The fm_smooth_er_coef is used to set this coefficient in the XGC-0 code through the namelist. The rho_b parameter controls the location of the transition. The fm_smooth_er_rhob variable is used to set this parameter in the code. The default values for these parameters are: C_{er}=75 and rho_b=0.95.