H. Arimoto et al., MACROSCOPIC BEHAVIOR AND DISCRETE DYNAMO IN HIGH-THETA REVERSED-FIELDPINCH DISCHARGES, Physics of fluids. B, Plasma physics, 5(6), 1993, pp. 1836-1841
The magnetohydrodynamic (MHD) activity and the discrete dynamo in high
-THETA reversed-field pinch (RFP) discharges are studied through compa
risons with those in normal-THETA RFP discharges, where THETA = B(thet
a)(a)/[B(z)] is the pinch parameter. In high-THETA RFP discharges, the
mode coupling of m = 1 is enhanced by the high magnetic shear configu
ration, and the MHD activity is more turbulent as compared with that i
n normal-THETA RFP discharges. Furthermore, the discrete increase of t
he toroidal magnetic flux is obviously observable. The increase of the
toroidal magnetic flux generated by the discrete dynamo, which has an
asymmetric structure in the toroidal direction, is only 1%-2% of the
whole toroidal magnetic flux. The experimental results indicate that t
he discrete dynamo does not play an essential role in the RFP dynamo.