Rotational effects on the m=1 magnetohydrodynamic instability in spheromaks

The effect of rotation on the magnetohydrodynamic stability of m=1 modes in spheromaks is calculated to reveal a threshold for rotational instability at ΩτA∼0.2, where Ω is the angular rotation frequency and τA is the Alfven transit time. This result may explain the appearance of m=1 modes in spheromak experiments in which the flux conserver aspect ratio L/R lies well below the threshold for the tilt instability (m=n=1). For flux conservers with aspect ratios above the tilt instability threshold, rotational instability dominates when ΩτA exceeds the rotational threshold