Two input files are generated based on XGC-A07 input file: (1) XGC-A08: same equilibrium and same input file, but older version of the code; (2) XGC-A09: same equilibrium, newer version of the code, but older version of the flow shear suppression model. Left panels show results for the case XGC-A08 and right panels show results for the caseXGC-A09
Results clearly indicated that the problem has been introduced during the recent merge with the svn repository.
The FMCFM changes has been synchronized with the version of the XGC-0 code from the svn repository. Gunyoung committed his changes related to the impurity radial model and get_mid_r bug. Theory motivated coefficient for the flow shear suppression factor is used. The simulation uses high resolution equilibrium provided by Rich Groebner. There are significant changes in the plasma density dynamics. It is not clear if these changes relate to (1) model for flow shear suppression factor; (2) new equilibrium; (3) other changes to the code. In order to isolate the problem, two new simulations are submitted: (1) XGC-A08: same equilibrium and same input file, but older version of the code; (2) XGC-A09: same equilibrium, newer version of the code, but older version of the flow shear suppression model.
Gunyoung has altered the original equilibrium that Jerry and Jim sent about two weeks ago to fit the XGC-0 requirements. The first XGC-0 simulation for this Alcator C-Mod equilibrium includes simplified model for the anomalous transport. The FMCFM interface is disabled.
The fm_web flows shear stabilization factor is decreased from to . as result, the effect of flow shear stabilization is significantly reduced for the whole plasma profile.
New XGC-0 namelist parameter is implemented in order to control parameter that is responsible for flow shear stabilization factor. According to Glenn’s notes, the fm_wexb coefficient should depend on :
Rich has sent an updated EFIT equilibrium for the DIII-D discharge 132014.03000. It has resolution of 129×129, kinetic equilibrium option enable and low EFIT error parameter. The TEQ code shows significantly lower residual in the near separatrix region as well.
Note that the plasma pressure profiles looks significantly different comparing to the lower resolution case at 3.023 sec (left figure below shows the derivate of the plasma pressure at 3.000 sec and right figure shows the derivative of the plasma pressure at 3.023 sec):
EFIT grid has been set to 129×129, number of iterations has been increased to 50, the namelist value for error has been decreased from 1.e-3 to 1.e-4. The resulting layout looks very similar. However, the normalized beta is reduced by about 3%. Analysis with TEQ still indicates relatively high residual error near the separatrix. This error might be related to different input options that might be associated with different account for the bootstrap current. There are differences in FF’ and q profiles that might be more difficult to understand. Some of equilibrium profiles are shown below. Left column shows profiles obtained with the new EFIT (129×129) run, while the left column shows profiles obtained with the old EFIT (65×65) run.
The tbl_diffusion_mode option is set to 3 to enable transition from FMCFM in the plasma core and old model in the SOL region. In addition, spacial variation is allowed in the SOL region by setting tbl_d_profile_on to 1. As result, the problem of accumulation of particles in the SOL region is resolved:
to 
. as result, the effect of flow shear stabilization is significantly reduced for the whole plasma profile.
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