Linear stability of the JET H-mode pedestal

H-mode Pedestal Characteristics and Mhd Stability of the Edge Plasma in Alcator C-mod

Under most operational conditions of Alcator C-Mod the dominant type of H-mode is the steady state enhanced Dα mode (EDA), characterized by good energy confinement, continuously degraded impurity confinement and absence of regular ELMs. In this regime a quasicoherent (QC) electromagnetic mode (kθ~5 cm, f~100 kHz) is observed, localized in the region of the density pedestal. Experimental evidenc...

The Role of Neutrals in H–mode Pedestal Formation

Global gyrokinetic simulations of the H-mode tokamak edge pedestal

Global gyrokinetic simulations of DIII-D H-mode edge pedestal show two types of instabilities may exist approaching the onset of edge localized modes: an intermediate-n, high frequency mode which we identify as the “kinetic peeling ballooning mode (KPBM),” and a high-n, low frequency mode. Our previous study [W. Wan et al., Phys. Rev. Lett. 109, 185004 (2012)] has shown that when the safety fac...

Linear gyrokinetic analysis of a DIII-D H-mode pedestal near the ideal ballooning threshold

Recent advances in GYRO allow simulations to map out the linear stability of many eigenvalues and eigenvectors of the gyrokinetic equation (as opposed to only the most unstable) at low computational cost. In this work, GYRO’s new linear capabilities are applied to a pressure scan about the pedestal region of DIII-D shot 131997. MHD calculations in the infinite-n limit of the ideal ballooning mo...

Evolution of the H-mode edge pedestal between ELMs

The evolution of edge pedestal parameters between edge-localized modes (ELMs) is analyzed for an H-mode DIII-D [J Luxon, Nucl. Fusion 42, 612 (2002)] discharge. Experimental data are averaged over the same sub-intervals between successive ELMs to develop data that characterize the evolution of density, temperature, rotation velocities, etc. over the interval between ELMs. These data are interpr...