Experimental study of the effect of a biased electrode grid attached to a limiter on plasma blob propagation in a toroidal confinement device using an ultrafast camera
The main goal of this experiment is studying how blob propagation can be affected by an electrode grid in the case of an toroidal geometry with open field lines. Studies in this field are meant to better understand blob propagation in the SOLs of magnetic fusion devices and to develop more appropriate devices for controlling heat and particle fluxes. From the analysis of this specific experiment, we can conclude that blob trajectories seem to be influenced by voltage biasing on the electrode grid via the induced ExB. The trajectory as well as the velocity in the case of horizontal or vertical biasing have behaviors that are visibly different from each other as well as from the unbiased case. In order to improve this analysis, the propagation of the blob structure as a whole could be analyzed from the existing data, especially in the case of vertical biasing in order to better interpret its specific behavior. Velocity of the coherent structure as a whole instead of a front velocity could also be analysed. Other sets of experiments keeping the same parameters would also be useful in order to confirm that the results of the plasma shots and of the conditional sampling analysis method are reproducible.