Closed Magnetic Traps with Rectilinear Sections

摘要

Aspects of plasma equilibrium and MHD stability in the Dracon closed magnetic trap which contains long rectilinear sections with a homogeneous magnetic field are discussed. Unlike racetrack stellarators, the equilibrium plasma pressure in the Dracon trap does not depend on the length of the rectilinear sections as a result of the incorporation of special connecting curvilinear elements. This system combines the positive qualities of open traps (high average beta and simple design of the rectilinear section) and closed systems (no plasma losses along field lines). The following topics are examined: (1) plasma equilibrium in a trap containing curvilinear elements with a three dimensional axis; (2) three methods of stabilizing flute perturbations; (a) by creating a magnetic well in the curvilinear elements using auxiliary helical windings; (b) by means of an anisotropic high-beta plasma confined in an additional minimum-B trap; (c) by a relativistic electron ring (bumpy-torous-type stabilization). Neoclassical theory is used to give preliminary estimates of plasma losses and to obtain approximate parameters of a fusion reactor.