Filamentary current detection in stellarator plasmas

In this work we present the experimental setup, combining edge, and x-ray d iagnostics, used to localize the currents generated by fast electrons confi ned near the plasma periphery in TJ-II plasmas. The method is similar to th at used for the experimental determination of the magnetic field mapping in stellarators, just intercepting the trajectories of test electrons. The fa ct that stellarators can keep magnetic structures "frozen" in vacuum during the field plateau enables the detection of local currents near the plasma periphery in the TJ-II stellarator. (C) 2001 American Institute of Physics.