Observation and analysis of particle drift islands in a torsatron

This is the authors' abstract. We don't add key points for this paper.

Magnetic islands in toroidal plasma confinement devices are generated by resonant magnetic error fields. Energetic particle drift surfaces can differ substantially from magnetic flux surfaces. In this Letter the first direct measurement of islands in energetic particle drift surfaces are presented. The understanding of these drift islands is important for the optimization of plasma confinement. These drift islands are demonstrated to form in energetic electron drift surfaces as a result of resonant magnetic field perturbations and resonant, applied electric field perturbations. The results, once corrected for inherent magnetic error fields, agree well with theoretical predictions.