Formation of edge pressure pedestal and reversed magnetic shear due to toroidal rotation in a tokamak equilibrium

Effects of a Toroidal Rotation on the Stability Boundary of the MHDModes in the Tokamak Edge Pedestal

Effects of a toroidal rotation are investigated numerically on the stability of the MHD modes in the edge pedestal, which relate to the type-I edge-localized mode (ELM). A new linear MHD stability code MINERVA is developed for solving the Frieman-Rotenberg equation, which is the linear ideal MHD equation with flow. As the result of the stability analysis, it is revealed that the sheared toroida...

Transport-driven toroidal rotation in the tokamak edge.

The interaction of passing-ion drift orbits with spatially inhomogeneous but purely diffusive radial transport is demonstrated to cause spontaneous toroidal spin-up in a simple model of the tokamak edge. Physically, major-radial orbit shifts cause orbit-averaged diffusivities to depend on v(∥), including its sign, leading to residual stress. The resulting pedestal-top intrinsic rotation scales ...

Effects of magnetic shear on toroidal rotation in tokamak plasmas with lower hybrid current drive.

Application of lower hybrid (LH) current drive in tokamak plasmas can induce both co- and countercurrent directed changes in toroidal rotation, depending on the core q profile. For discharges with q(0) <1, rotation increments in the countercurrent direction are observed. If the LH-driven current is sufficient to suppress sawteeth and increase q(0) above unity, the core toroidal rotation change ...

PUBLISHED VERSION Effects of Magnetic Shear on Toroidal Rotation in Tokamak Plasmas with Lower Hybrid Current Drive

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...