Rotation of Interchange Instability in the Large Helical Device

Abstract

The rotation of resistive interchange instabilities excited in the periphery of plasmas compared to plasma flows under various plasma conditions in the Large Helical Device. The observed magnetohydrodynamic modes exhibit nominal rotation in the electron diamagnetic direction in the laboratory frame. We assumed that the ion (electron) flows consist of the E × B and ion (electron) diamagnetic drift flows. These drift flows were individually evaluated and geometrically compensated using a finite beta equilibrium. Experiments with different neutral beam injection conditions and different electron densities show that the frequencies of the observed modes were quantitatively consistent with those of the electron flow.