Global dynamo in a reversed field pinch plasma

We found that an RFP dynamo uniformly generates most of the toroidal flux along the toroidal direction in an RFP plasma with a high magnetic Reynolds (S) number. Hereafter we call it the global dynamo. The toroidal flux generated by the global dynamo is proportional to the plasma current. The effective inductance (proportional constant) increases with the S number and is kept at a constant value against the change of the plasma current. This means that the pinch parameter Θ is held constant; that is, the global dynamo has a self-organizing effect sustaining a particular RFP magnetic field configuration. By comparison with simulation results and analysis of magnetic fluctuations. We confirmed that the global dynamo is generated by the single helicity m (poloidal mode number) = 1 mode alone. (author)