Comparison between kinetic-ballooning-mode-driven turbulence and ion-temperature-gradient-driven one

Maeyama, Shinya; Ishizawa, Akihiro*; Watanabe, Tomohiko*; Nakata, Motoki; Idomura, Yasuhiro   

The normalized plasma pressure beta is one of the important parameters to the improvement of the magnetic plasma confinement. It is important to understand how the high-beta turbulence differs from the low-beta (or electrostatic) turbulence and to predict transport levels in the high-beta regime. We have recently extended the gyrokinetic Vlasov simulation code GKV to the electromagnetic version, which enables us to simulate kinetic-ballooning-mode-driven (KBM) turbulence in a high-beta regime, as well as ion-temperature-gradient-driven (ITG) turbulence in a low-beta regime. It is found that KBM turbulence causes the smaller ion energy flux than ITG turbulence, even when they have similar values of the maximum linear growth rate. This is due to not only the smaller amplitude of the perturbations but also the smaller phase factor in KBM turbulence than those in ITG turbulence.