A GLOBAL DYNAMO IN A REVERSED-FIELD PINCH PLASMA

It is found that a reversed-field pinch (RFP) dynamo uniformly generat es most of the toroidal flux in a RFP plasma with a high magnetic Reyn olds (S) number. Hereafter, this is referred to as the global dynamo. The toroidal flux generated by the global dynamo is proportional to th e plasma current. The effective inductance in a RFP plasma increases w ith S number and remains constant against the changing plasma current. This means that the pinch parameter THETA is held constant, that is, the global dynamo has a self-organizing effect sustaining a particular RFP configuration. By comparing simulation results and analysis of ma gnetic fluctuations, it is confirmed that a global dynamo is generated by the nonlinear evolution of the single-helicity of the m = 1 mode a lone.