Investigation of electron-distribution function and dynamo mechanisms in areversed-field pinch by analysis of hydrogen-pellet deflection

In reversed-field pinches, two different mechanisms have been proposed to e xplain the dynamo process which drives the poloidal current needed to susta in the magnetic configuration: the kinetic dynamo theory and the magnetohyd rodynamic (MHD) dynamo theory. Experimentally, they can be distinguished by the radial behavior of the electron distribution function. In this Letter the trajectory deflection of frozen hydrogen pellets ha:, been used as a di agnostic of suprathermal electrons in the plasma. Thr classical Spitzer-Har m distortion of the electron distribution Function consistent with the MHD dynamo electric field is found to give a better modeling of the pellet traj ectory.