Relation between toroidal flux generation and deformation of the plasma column in reversed-field pinch

Plasma behavior during formation of reversed-field configuration was examined using a reversed-field pinch apparatus capable of observing optically the whole plasma image. Temporal change of the displacement of poloidal mode 1 of the plasma column was obtained by framing photographs of the plasma column, so the correspondence was studied of field distribution, poloidal mode 0 and 1 of toroidal field at the discharge tube wall, toroidal flux, and toroidal circuit voltage. The displacement of the plasma column grows large in the vicinity of the time when the toroidal flux starts to increase. Then, during the time when the toroidal flux decreases, the current density in axial direction grows large at the middle of the discharge tube. Poloidal mode 1, larger than 0, 2 and 3, of toroidal field at the wall was explained by calculating the growth rate of instability. (Mori, K.)