Results of edge plasma investigation in a minimum-B region of the GAMMA 10
tandem mirror are described. In this experiment, the spatial profile of the
ion saturation current and the floating potential in the edge plasmas are
measured by using arrays of Lanpmuir probes installed on conducting plates
in anchor cells together with a movable probe near the plate in the east an
chor cell. From these measurements, a significant asymmetry to the axis of
the plasma was observed in both probe currents and floating potentials. It
is also found that there are some impurity-deposited layers partially obser
ved on all the conducting plates and that their locations show a rotational
symmetry to the magnetic axis at 180 degrees. In this region, a strong gra
dient of the magnetic field strength toward the axis exists. The direction
of the expected plasma shift corresponds to the <(<del>)over bar>B and curv
ature drift for ions. The results of ion orbit calculation taking account o
f the above effect show a good agreement with the measured results. (C) 200
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