Benchmarking of the Gyrokinetic Microstability Codes GENE, GS2, and GYRO over a Range of Plasma Parameters

Comparing results from different gyrokinetic codes as a means of verification (benchmarking) is only convincing if the codes agree over a wide range of plasma conditions. Otherwise, agreement may simply be fortuitous. We present here linear and nonlinear comparisons of the Eulerian codes GENE, GS2, and GYRO for a variety of discharges and radii. These include the outer regions of DIII-D discharges with localized electron-cyclotron heating applied at different locations, the steep-gradient region of an EAST H-mode pedestal, a high poloidal beta DIII-D discharge with reversed magnetic shear in the core, and well-matched DIII-D discharges with varying degrees of toroidal rotation.