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

The fluctuation-induced Hall electromotive force, $\langle \delta \overrightarrow{J}\times \delta \overrightarrow{B}\rangle /n_{e}e$, 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.