Investigation of edge plasmas in the anchor cell region of GAMMA 10

The first results of Langmuir probe measurements at the outer transition re gion of the anchor cell of GAMMA10 are given. A probe current asymmetry in vertical direction is found in this region. It is also found that the asymm etry of probe current increases in outward direction and the direction of t he asymmetry is independent on movable limiter position. A relation of this plasma asymmetry with the main magnetic field configuration is investigate d. Plasma flow through the non-axisymmetric magnetic field configuration re gion is thought to be the source of plasma asymmetry in this region, i.e., del E and curvature drifts are responsible for the asymmetry. Possibility o f cold plasma formation in the anchor cell region is obtained during plug e lectron cyclotron resonance heating (ECRH) and can be explained with the de sorption of particles due to the collision of the drifted out particles wit h the wall.