Relationship between edge magnetic field and rotation of the spatial structure of visible light emitted from low aspect RFP plasmas on RELAX

The relationship between the edge toroidal field B_t and the rotation of the spatial structure of visible light emitted from reversed field pinch (RFP) plasmas is reported. The rotation of the spatial structure of visible light is captured by a high-speed camera attached to a horizontal viewing port of the RELAX , which was designed for RFP experiments. It is found that the rotation velocity and the direction of the spatial structure of visible light depend on B_t. In the non-reversal case, the structure rotates in the co-current direction, while in the counter-current direction in the reversal case. The frequency and direction of the spatial structure of visible light are consistent with magnetic fluctuations measured by magnetic probes.(author)