We investigate the effect of drift kinetic damping on the resistive wall mode (RWM), due to the mode resonance with magnetic precession drifts and/or bounce motion of bulk plasma thermal particles. A self-consistent toroidal drift kinetic model is developed and incorporated into the MHD code MARS-F [Y.Q. Liu, et al., Phys. Plasmas 7, 3681 (2000)]. The new code (MARS-K) is used to study the RWM ...

First experiments with nonaxisymmetric magnetic perturbations, toroidal mode number n=2, produced by newly installed in-vessel saddle coils in the ASDEX Upgrade tokamak show significant reduction of plasma energy loss and peak divertor power load associated with type-I edge localized modes (ELMs) in high-confinement mode plasmas. ELM mitigation is observed above an edge density threshold and is...

The MHD mode trajectory in the Madison Symmetric Torus reversed-field pinch has been found to obey the sine-Gordon equation. Corresponding to experiment, a perturbation analysis predicts the locations of mode locking to be at the vacuum chamber poloidal and/or toroidal gaps. The mode's energy dissipates when it locks, as shown by a decaying spiral phase-plane trajectory. Unlocked modes travel a...

High power chemical lasers often have high aspect ratio gain regions, for which an unstable resonator with different magnifications in the two transverse dimensions is desirable. This paper considers a new class of unstable resonators which achieves the differential magnification property with spherical mirrors by suitably tilting the mirrors through large angles. Output optical quality has bee...

Motivated by experimental observations of apparently triggerless tearing modes, we have performed linear and nonlinear MHD analysis showing that a non-resonant mode with toroidal mode number n=1 can develop in the National Spherical Torus eXperiment (NSTX) at moderate normalized βN when the shear is low and the central safety factor q0 is close to but greater than one. This mode, which is relat...

Motivated by experimental observations of apparently triggerless tearing modes, we have performed linear and nonlinear MHD analysis showing that a non-resonant mode with toroidal mode number n = 1 can develop in the National Spherical Torus eXperiment (NSTX) at moderate normalized βN when the shear is low and the central safety factor q0 is close to but greater than one. This mode, which is rel...

In the present work, we analyse the two dimensional (2-D) mode structures and global stability of the Alfvkn branches, whose frequencies are close to the toroidicity induced A1fv.h continuum gap. The fully 2-D problem is solved using a two spatial-scale WKBJ formalism without employing perturbation theory in treating drive and damping terms. A code that solves the 2-D mode structures and global...

A ballooning perturbation in a toroidally rotating tokamak is expanded by square-integrable eigenfunctions of an eigenvalue problem associated with ballooning modes in a static plasma. Especially a weight function is chosen such that the eigenvalue problem has only the discrete spectrum. The eigenvalues evolve in time owing to toroidal rotation shear, resulting in a countably infinite number of...