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A new understanding of edge localized modes (ELMs) in tokamak discharges is emerging (Snyder P B et al 2002 Phys. Plasmas 9 2037), in which the ELM is an essentially ideal magnetohydrodynamic (MHD) instability and the ELM severity is determined by the radi ...
Magnetohydrodynamic (MHD) instabilities can limit the performance and degrade the confinement of tokamak plasmas. The Tokamak à Configuration Variable (TCV), unique for its capability to produce a variety of poloidal plasma shapes, has been used to analyse ...
Global Alfven eigenmodes are studied using two different models for the plasma and the results compared with the instability threshold measured experimentally. Fluid-resistive models predict that continuum damped toroidicity induced Alfven modes (TAE) are ...
Reversed magnetic shear is associated with large negative surface averaged parallel current densities that increase in magnitude towards the plasma edge and guarantee stability at large beta in tokamaks. The surface averaged parallel current density is sma ...
A numerical study of the free-boundary axisymmetric (n = 0) ideal magnetohydrodynamical (MHD) motions of the EXTRAP device is presented. The dependence of stability on current profiles in the plasma and currents in the external conductors is investigated. ...
The highest volume averaged beta values beta (t) of 2.2% at B-t = 0.75 T (gas puff) and 2.4% at D-t = 1.3 T (pellet) in helical devices have been achieved in LHD. The beta (t) dependence of MHD activities has been investigated in NBI plasmas. The n/m = 1/2 ...
Recent experimental results in the Large Helical Device have indicated that a large pressure gradient can be formed beyond the stability criterion for the Mercier (high-n) mode. While the stability against an interchange mode is violated in the inward-shif ...
Concerns about the flexibility and robustness of a compact quasiaxial stellarator design are addressed by studying the effects of varied pressure and rotational transform profiles on expected performance. For thirty, related, fully three-dimensional config ...
Stability limits of highly elongated, D-shaped plasmas have been measured in the TCV (tokamak a configuration variable) tokamak. It is found that the plasma current is limited by kink-type disruptions, preceded by magnetohydrodynamic (MHD) mode activity. T ...
Magnetohydrodynamic (MHD) stability limits for the n = 1 internal kink mode in a tokamak are investigated. As the intemal kink mode is a weak instability, accurate equilibrium solutions are required to determine its stability boundaries. For this purpose, ...
