Vol.27 No.4(3) [2005]

Spatio-Temporal Behavior of Bistable Density Transition in Magnetized Plasma

Shunjiro SHINOHARA, Katsuhisa SUGIMORI, Yasushi NAKAMURA and Masatoshi YAGI


Self-excited bistable transition phenomena have been investigated by voltage biasing to an inserted electrode of a radio frequency (rf)-produced, magnetized plasma. Spatio-temporal behaviors of global, density transitions and back ones between two states (flip-flop pattern) have been measured, as to the ion saturation current Iis and floating potential Vf in the bulk plasma and near the electrode regions. Transition time Ttr between two states was dependent on the bulk region, and it was less than ms and 〜 a few ms for Iis and Vf, respectively. On the other hand, Ttr was very small for the bias current on the order of 〜 μs, and it was also small for Iis and Vf, which have less than a few tens of μs near the electrode region, where structural changes of plasma potential and density were observed at the transition. These showed the importance of the sheath, electrode region to trigger the transition coming from the two-dimensional particle balance and motion with sheath type instabilities.