Effects of Toroidal Magnetic Field on an Annular Plasma

An experimental investigation on some effects of the toroidal magnetic field on an annular plasma produced by a modified hard-core θ-pinch is described. The length of the annular plasma could by varied by a pair of end coils. A high speed camera, a floating double probe and a magnetic probe were used for the investigation. The experimental results show that the toroidal magnetic field has some effects to suppress the macroscopic instabilities, such as the positional instability, and the axial contraction of the annular plasma, where the former was observed in the case with the shorter annular plasma and the latter in the case with the longer one when the toroidal field was not applied.