Numerical simulations of the Princeton magnetorotational instability experiment with conducting axial boundaries

Abstract

We investigate numerically the Princeton magnetorotational instability (MRI) experiment and the effect of conducting axial boundaries or endcaps. MRI is identified and found to reach a much higher saturation than for insulating endcaps. This is probably due to stronger driving of the base flow by the magnetically rather than viscously coupled boundaries. Although the computations are necessarily limited to lower Reynolds numbers (Re) than their experimental counterparts, it appears that the saturation level becomes independent of Re when Re is sufficiently large, whereas it has been found previously to decrease roughly as Re-1/4 with insulating endcaps. The much higher saturation levels will allow for the positive detection of MRI beyond its theoretical and numerical predictions.