Ahn, Hee-KapBrass, PeterCheong, OtfriedNa, Hyeon-SukShin, Chan-SuVigneron, Antoine

Given a planar convex set C, we give sublinear approximation algorithms to determine approximations of the largest axially symmetric convex set S contained in C, and the smallest such set S′ that contains C. More precisely, for any var epsilon>0, we find an axially symmetric convex polygon Qsubset ofC with area |Q|>(1−var epsilon)|S| and we find an...

In this paper we focus our attention on rotationally symmetric problems, where cylinder coordinates are suitable. For Cartesian grid arrangements finite-difference schemes for the diffusion equation in two spatial dimensions are introduced. The temporal evolution is determined by implicit and explicit techniques. In addition to exactly solvable dif...

Using the 'virtual casing' principle the parallel MFBE2001 code computes the magnetic field of three-dimensional ideal MHD equilibria in a form suitable for tracing field lines and guiding centres. This report gives a detailed description of theory, numerical methods and use of MFBE2001. Examples for tokamak, currentless stellarator and quasi-axisy...

A characteristic feature of modes in the continua (''Alfven'' and ''slow'') of magnetohydrodynamics (MHD) is their singularity at a magnetic surface #psi# #psi#_0. For axisymmetric toroidal configurations the dependence of continuum modes on the distance #psi#-#psi#_0 is reexamined. It is found that, in general, the normal component #xi#_#psi# of t...

The resistive ballooning mode equations are cast in a new form appropriate for evaluation near the plasma edge of toroidal (axisymmetric as well as three-dimensional) configurations, where the resistive ballooning effects outweigh the diamagnetic effects. Explicit evaluation is carried out for cylindrically symmetric plasmas and for a tokamak model...