This program treats theoretically low frequency linear and nonlinear wave processes in magnetized plasmas. A primary objective has been to evaluate the effectiveness of MHD waves to heat plasma and drive current in toroidal configurations. The research covers the following topics: (1) the existence and properties of the MHD continua in plasma equilibria without spatial symmetry; (2) low frequen...

Magnetohydrodynamic instabilities of high-mode (H-mode) pedestal are investigated in this paper with the inclusion of bootstrap current for equilibrium and rotation for stability. The jointed European torus-like equilibria of H-mode discharges are generated numerically using the VMEC code. It is found that, when the bootstrap current is taken into account, a safety-factor reversal or plateau ca...

The work deals with one of the topics of collective motion. In the frame of Nuclear Fluid Dynamics, a model which portrays the nuclear matter as a quantum elastic body, the torus-like motions and their associated energies are computed using the thirteen moment approximation. Such excitations correspond to the Hill vortex known from classical Hydrodynamics. There are also calculated the nonvanis...

Global gyrokinetic toroidal code (GTC) is used to study the low-frequency modes in tokamaks including geodesic acoustic mode (GAM) and beta-induced Alfvén eigenmode (BAE). GAM and BAE have the same frequency due to the geodesic curvature and thermal particle compressibility in toroidal plasmas. Important new insights include: the collisionless damping rate of the GAM is greatly enhanced by trap...

Using a magnetohydrodynamics numerical code that includes the description of density and pressure evolution and anisotropic thermal conductivity, it is shown that single-helicity states in the reversed-field pinch (RFP) configuration are obtained when the resistivity has a radial profile sharply increasing close to the wall. In contrast, a uniform resistivity produces multiple-helicity states. ...

Neutral atoms in the tokamak edge affect the electric field and plasma flow through charge exchange. Here, it is shown that these effects depend sensitively on the poloidal location of the atoms. It is found that the radial electric field and toroidal flow velocity in a collisional edge plasma are largest if the atoms are concentrated on the inboard side. This feature may explain MAST and COMPA...

In a major upgrade, the (2D) electron cyclotron emission imaging diagnostic (ECEI) at ASDEX Upgrade has been equipped with a second detector array, observing a different toroidal position in the plasma, to enable quasi-3D measurements of the electron temperature. The new system will measure a total of 288 channels, in two 2D arrays, toroidally separated by 40 cm. The two detector arrays observe...

In this Letter, the linear stability of the resistive wall modes (RWMs) in toroidal geometry for a reversed field pinch (RFP) plasma is studied. Three computational models are used: the cylindrical code ETAW, the toroidal MHD code MARS-F, and the CarMa code, able to take fully into account the effects of a three-dimensional conducting structure which mimics the real shell geometry of a reversed...