Gyrokinetic particle simulation of finite-β modified ion temperature gradient drift instabilities

A linearized gyrokinetic particle simulation of finite-β modified ion temperature gradient drift instabilities (ηi modes) is presented and compared with the results from a linear integral eigenmode code. In the electrostatic limit, an extra term in the resonant denominator due to the finite Larmor radius effects has been shown to play an important role in determining the mode structures for the modes with kperpendicularρi ∼ O(1). This term is automatically included in the gyrokinetic simulation model, but not in the usual linear eigenmode equations. The effects of this Linsker's term in the finite-β limit are the focus of the present investigation. The nonlinear evolution of the finite-β modified ηi modes is also discussed. 2 refs