Fitting Mode

Overview | What is EFIT? | History | Fitting Mode | Equilibrium Mode

Fitting mode is the default solution method in EFIT. It may also be selected explicitly by specifying ICONVR=1 or 2 in the namelist IN1. In fitting mode, there are two main input options to run EFITD. In the SNAP mode 3, all the input variables are specified in the EFIT_SNAP.DAT file. EFITD will first look into the user local area for the SNAP file. If none is available, it will then use a set of default parameters from the SNAP file in the EFIT: area. There are three available SNAP files in the EFIT: area, a brief description of the input variables to the SNAP file can be found at the end of each file :

• EFIT_SNAP.DAT_DEF:

defaulted SNAP file, no edge gradients. For L-mode discharges, break-down error field analysis. Polynomial representation. No edge current.

• EFIT_SNAP.DAT_J:

finite edge gradients included in the current representation.

• EFIT_SNAP.DAT_JT:

Edge gradients constrained to vanish weakly. For H-mode discharges. Polynomial representation. Edge current is constrainted to vanish weakly.

• EFIT_SNAP.DAT_SCRAPE:

force-free scrape-off layer and vessel currents included in the fitting.

• EFIT_SNAP.DAT_MSES:

For L- and H- mode discharges with MSE. Spline representation. Finite edge current allowed.

• EFIT_SNAP.DAT_MSE2_J1:

MSE plus constrainted edge J.

A SNAP_EXT mode (mode 7) is also available. This is similar to SNAP mode, except EFIT asks for the SNAP file extension from the user. This can be used to do time-dependent analysis.

A second way to enter input data for fitting is to use the FILE mode 2. In this case, mode 5 must first be run to make the Kssssss.ttttt file which contains the required data in the namelists IN1 and INWANT. Kinetic profile data can also be optionally used in conjunction with the usual external magnetic data in the fitting. Polarimetry data such as MSE can also be optionally used. The input data is in the namelist INS.