Damping of magnetospheric toroidal Alfvén eigenmodes due to phase mixing

We demonstrate that toroidal shear Alfvén eigenmodes in dipolar magnetostatic plasma equilibrium are subject to damping due to phase mixing. This result is of particular interest for the investigation of Pc5-6 geomagnetic pulsations

Resistive g-modes in a reversed field pinch plasma

First direct experimental evidence of high frequency, high toroidal mode number (n>20), magnetic fluctuations due to unstable resistive interchange modes (g-modes) resonant in the edge region of a reversed field pinch (RFP) plasma is presented. Experimental characterization of time and space periodicities of the modes is provided by means of highly resolved in-vessel edge and insertable magnetic diagnostics. It is found that the spectral mode properties are in good agreement with the predictions of the theoretical linear resistive magnetohydrodynamic stability analysis. A simple model is proposed for the observed saturation levels of the modes.Comment: Submitted to Physical Review Letter