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P: Plasmaphysik

P 25: Magnetischer Einschluß (Poster)

P 25.2: Poster

Monday, March 9, 1998, 18:00–20:00, P 2

Ion-Temperature-Gradient Instability in a Θ-Pinch Drift-Kinetic Plasma-Equilibrium — •C. Nührenberg — IPP-EURATOM Association, Teilinstitut Greifswald, 17489 Greifswald, Germany

Aim of this work is to study plasma instabilities, which are driven by gradients of the plasma ion-temperature, in the drift-kinetic framework. Here, the main ingredients of the plasma description are (i) two drift-kinetic equations for ions and electrons in the five-dimensional space composed of three space-variables, which are given in magnetic coordinates, and two adiabatic invariants of motion, the first of which is the magnetic moment; (ii) the quasi-neutrality condition; (iii) a magnetohydrodynamic plasma equilibrium. Since in a sequence of equilibria adequate to approximate the Wendelstein 7-X stellarator the Θ-pinch is the simplest one, it will be analyzed here. A Maxwellian is employed as equilibrium distribution function and a linear stability theory is derived. Preliminary results show that purely growing perturbations — with growth rates approximately poloidal mode number times about a tenth of the magnetic drift — exist for temperature gradients steeper than those of the particle density (η ≥ 1) independently of the plasma equilibrium-β, which is the ratio of the internal plasma energy density and the magnetic field energy density.