Particle confinement in axisymmetric poloidal magnetic field configurations with zeros of B: Methodological note

• Published in: Plasma physics reports 2005-12, Vol.31 (12), p.1003-1011
• Main Authors: Arsenin, V. V., Skovoroda, A. A.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AXIAL SYMMETRY; DIVERTORS; LARMOR RADIUS; MAGNETIC FIELDS; MAGNETIC MOMENTS; MAGNETIC SURFACES; PLASMA; PLASMA CONFINEMENT; WALL EFFECTS
• ISSN: 1063-780X; 1562-6938
• DOI: 10.1134/1.2147646

Collisionless particle confinement in axisymmetric configurations with magnetic field nulls is analyzed. The existence of an invariant of motion--the generalized azimuthal momentum--makes it possible to determine in which of the spatial regions separated by magnetic separatrices passing through the magnetic null lines the particle occurs after it leaves the vicinity of a magnetic null line. In particular, it is possible to formulate a sufficient condition for the particle not to escape through the separatrix from the confinement region to the external region. In the configuration under analysis, the particles can be lost from a separatrix layer with a thickness on the order of the Larmor radius because of the nonconservation of the magnetic moment {mu}. In this case, the variations in {mu} are easier to describe in a coordinate system associated with the magnetic surfaces. An analysis is made of the applicability of expressions for the single-pass change {delta}{mu} in the magnetic moment that were obtained in different magnetic field models for a confinement system with a divertor (such that there is a circular null line)