Experimental studies of magnetic surfaces in Heliotron DM

Abstract

The structure of the magnetic surfaces in Heliotron DM is measured by the pulsed-electron-beam method. The shape of the observed magnetic island is described. By improving the helical-coil feeder and using compensation coils, the magnetic islands can be eliminated, and finally a value of the rotational transform that agrees well with the computed one up to ι/2π ≅ 2 is obtained.