A helically symmetric stellarator (HSX)

The Helically Symmetric Experiment (HSX) is a quasi-helically symmetric (QH S) stellarator currently under construction at the Torsatron/Stellarator La boratory of the University of Wisconsin-Madison. This device is unique in i ts magnetic design in that the magnetic field spectrum possesses only a sin gle dominant (helical) component, This design avoids the large direct orbit losses associated with conventional stellarators. The restoration of an ig norable coordinate in the confining magnetic field makes this device analog ous to an axisymmetric q = 1/3 tokamak with respect to neoclassical confine ment.