U. Schwenn

Methods for the efficient calculation of the magnetohydrodynamic (MHD) stability properties of magnetically confined fusion

A magnetohydrodynamic (MHD) model is applied to the problem of the stability of magnetically confined ther monuclear plasmas of interest in the pursuit of fusion power. Previous studies limited to two-dimensional con figurations are here generalized to three-dimensional toroidal plasmas. Using finite Fourier representations in the angle coordinates and finite hybrid elements in the radial direction, we solve the discretized Euler-Lagrange equations to determine the linear stability properties of the plasma.

Fully three‐dimensional ideal magnetohydrodynamic stability analysis of low‐n modes and Mercier modes in stellarators

The terpsichore three‐dimensional linear ideal magnetohydrodynamic (MHD) stability code [Theory of Fusion Plasmas, Proceedings of the Joint Varenna–Lausanne International Workshop, Chexbres, Switzerland, 1988 (Editrice Compositori, Bologna, Italy, 1989), p. 93; Controlled Fusion and Plasma Heating, Proceedings of the 17th European Conference, Amsterdam, The Netherlands (European Physical Society, Petit‐Lancy, Switzerland, 1990), Vol. 14B, Part II, p. 931; Theory of Fusion Plasmas, Proceedings of the Joint Varenna–Lausanne International Workshop, Valla Monastero, Varenna, Italy, 1990 (Editrice Compositori, Bologna, Italy, 1990), p. 655] has been extended to the full MHD equations. The new code is used to calculate the physical growth rates of nonlocal low‐n modes for l=2 torsatron configurations. A comprehensive investigation of the relation between the Mercier modes and the low‐n modes has been performed. The unstable localized low‐n modes are found to be correlated with the Mercier criterion. Finite grow...

Field Line Diversion Properties of Finite β-Helias Equilibria

The diversion properties of the magnetic field outside the last closed magnetic surface of a Helias stellarator configuration [Phys. Lett. A 114 (1986) 129; Phys. Lett. A 129 (1988) 113] are investigated for finite pressure equilibria. The results indicate that a divertor concept which has been developed from the diversion properties of the corresponding vacuum field can be maintained for finite pressure equilibria. Cross-field particle transport is simulated by a simplified scrape-off layer (SOL) model.

Three-Dimensional Ideal Magnetohydrodynamic Stability on Parallel Machines

On the path towards a thermonuclear fusion reactor there are several technological and physical uncertainties to be understood and solved. One of the most fundamental problems is the appearance of many sorts of instabilities which can either enhance the energy outflow or even destroy the magnetic confinement of the fusion plasma. The knowledge of such instabilities is a prerequisite to a good understanding of the behaviour of actual experiments, and to the design of new devices. Most of the effort is devoted to the study of axisymmetric toroidal configurations such as tokamaks or spheromaks and to helically twisted toroidal devices such as stellarators.

Ideal magnetohydrodynamic stability computations for three-dimensional magnetic fusion devices

Reference CRPP-ARTICLE-1991-020doi:10.1016/0045-7825(91)90067-GView record in Web of Science Record created on 2008-04-16, modified on 2017-05-12