The role of m=0 modal components in the reversed-field-pinch dynamo effect in the single fluid magnetohydrodynamics model

The role of the m=0 modal components on the reversed-field-pinch (RFP) dynamo effect is examined in the single fluid magnetohydrodynamic (MHD) model by comparing results with and without various nonlinear convolutions of the m=0 spectrum. Results indicate that the dynamo effect comes directly from the m=1 instabilities and the effect of other nonlinear convolutions is small. Scaling studies of δB/B with the Lundquist number (S) are also performed. It is found that δB/B is independent of S (diffusionlike scaling), which is consistent with the view that the dynamo effect arises directly from the m=1 modes.