Measurement of the Hall Dynamo Effect during Magnetic Reconnection in a High-Temperature Plasma

The fluctuation-induced Hall electromotive force, $\ensuremath{\langle}\ensuremath{\delta}\stackrel{\ensuremath{\rightarrow}}{J}\ifmmode\times\else\texttimes\fi{}\ensuremath{\delta}\stackrel{\ensuremath{\rightarrow}}{B}\ensuremath{\rangle}/{n}_{e}e$, is experimentally measured in the high-temperature interior of a reversed-field pinch plasma by a fast Faraday rotation diagnostic. It is found that the Hall dynamo effect is significant, redistributing (flattening) the equilibrium core current near the resonant surface during a reconnection event. These results imply that effects beyond single-fluid MHD are important for the dynamo and magnetic reconnection.