The Helically Symmetric Experiment, (HSX) Goals, Design and Status

Abstract

HSX is a quasi-helically symmetric (QHS) stellarator currently under construction at the Torsatron-Stellarator Laboratory of the University of Wisconsin - Madison. This device is unique in its magnetic design in that the magnetic field spectrum possesses only a single dominant (helical) component. This design avoids the large direct orbit losses and the low-collisionality neoclassical losses associated with conventional stellarators. The restoration of symmetry to the confining magnetic field makes the neoclassical confinement in this device analogous to an axisymmetric q = 1/3 tokamak.The magnet coil design has been attained through the application of the HELIAS1 approach developed at IPP Garching. The 48 modular twisted coils produce a magnetic field with R0 = 1.2 m, = .15 m, 0 = 1.04, a = 1.11, V” ~ -.6% (well), and B < 1.4 T. Plasma production and heating will be accomplished with the application of up to 200 kW of 28 GHz Electron Cyclotron Resonant Heating (ECRH).The HSX device has been designed...