Energy transfer to zonal flow and stable finite n modes, where n is the toroidal mode number, are proposed to be the main saturation mechanisms of the kinetic ballooning mode (KBM) in the deep core of a representative hybrid scenario in ASDEX-upgrade. This discharge is characterized by a low magnetic shear and high ion temperature gradient. The predicted transport flux induced by KBM can be experimentally relevant specifically when the magnetic shear is low (), consistent with experimental characteristics of hybrid plasmas. Under such a parameter space, energy transfer to zonal flow and stable finite n mode is important in saturating KBM, while the role of both zonal current and zonal corrugation of kinetic profiles is tiny.
This paper investigates the main mechanisms that limit the growth of the kinetic ballooning mode (KBM) in a hybrid plasma scenario in the ASDEX-Upgrade tokamak. The authors propose that energy transfer to zonal flow and stable finite-n modes are the primary saturation mechanisms, particularly when the magnetic shear is low. This is relevant for understanding the transport characteristics of hybrid plasmas.