January 21, 2010 | Integrated Modeling of Tokamak Plasmas

Case XGC-219 uses new expression for the ExB flow shear rate

Case XGC-219 has the same input as case XGC-216 but uses an improved expression for the ExB flow shear rate.

The ExB flow shear rate has been implemented as simple derivative of the radial electric field with respect to minor radius:

$omega_{rm ExB}equivfrac{partial E_r}{partial r}.$

New implementation is according to Ref. [T.S. Hahm and K.H. Burrell Phys. Plasmas 2, 1648 (1995)]:

$omega_{rm ExB}equiv left|frac{R B_theta}{B_phi}frac{partial}{partial r} left(frac{E_r}{R B_theta}right)right|,$

where $B_theta$ and $B_phi$ are the poloidal and toroidal components of the magnetic field.

The FMCFM interface is modified and particle diffusivity is updated for this case with tbl_d_coeff_in;:

fm_ion_diff_norm%particle(i) = tbl_d_coeff_in * fm_norm_diff

The particle diffusivity in the core region is selected to be $0.01 m^2/sec$ .