Behavior of the Edge Plasma near the Anchor Conducting Plates and Their Effect on the Plasma Gonfinement in the GAMMA 10 Tandem Mirror

This paper describes the behavior of the edge plasmas near conducting plates installed for improving the plasma performance of GAMMA 10. The conducting plates are fixed closely to the plasma surface where the cross section of the plasma is flatly elongated in the anchor transition region. In this region a significant asymmetry of the edge plasma was observed in both probe currents and floating potentials. The direction of the shift in the ion-saturation current corresponds to the gradient B drift for ions. It is also found that the deposition areas observed on the conducting plates, which show a rotational symmetry to the magnetic axis, are expanding with the progress of plasma experiments. Most probable mechanism explaining the above-observed results is discussed based on the results of the magnetic field and ion orbit calculations. Effects on the plasma parameters of the conducting plates are studied and it is found that the floating condition of the plates leads to the increase of the plasma performance during potential formation.