Linear comparison of gyrokinetic codes with trapped electrons

Rewoldt, G.*; Lin, Z.*; Idomura, Yasuhiro   

Three codes that solve the gyrokinetic equation in toroidal geometry are compared in the linear limit for the growth rates and real frequencies of the ion temperature gradient (ITG) mode and the trapped electron mode (TEM). The three codes are the gyrokinetic toroidal code (GTC) and GT3D, both of which are radially-global particle-in-cell initial value codes, and FULL, which is a radially-local continuum eigenvalue code. With the same standard input parameters on a reference magnetic surface, the three codes give good agreement for the linear eigenfrequencies, both without (i.e., with adiabatic electron response) and with trapped electrons, as the perpendicular wavenumber and the ion temperature gradient input parameters are varied.