Edge impurity ion heating from toroidally localized magnetic reconnection in a reversed field pinch plasma

Edge impurity ion heating associated with toroidally local magnetic reconnection events have been observed in MST, and show characteristics of ion cyclotron damping of Alfven waves or stochastic heating. MST is capable of operating in an improved confinement regime that reduces m = 1 tearing instabilities and associated global reconnection events. In these periods of reduced tearing activity,there are occasionally short bursts of radially and toroidally localized $m = 0$ magnetic activity, referred to as $m = 0$ bursts. These $m = 0$ bursts excite turbulence that quickly travels around the torus. Heating of C and Al impurities are observed within an sample time ($20\mu s$), independent of toroidal location. The impurity heating further demonstrates significant anisotropy and charge to mass ratio dependence, as expected for ion cyclotron or stochastic heating. Unlike previous observations of impurity ion heating associated with global reconnection events, this work show global heating resulting from local reconnection. This research is supported by US DOE.