MHD-perturbations in T-10

Installation of the soft X-ray imaging system on the T-10 tokamak allows to investigate the internal structure of the plasma perturbations during the three different type of the magnetohydrodynamic instabilities sawtooth crashes, minor and major disruptions. As was pointed out before the minor and major disruptions were predominantly characterized by the m/n=2/1 mode which is localized in the outer part of the plasma column. But experiments on JET indicated that the density limit disruptions were proceeded also by the m=1,n=1 'erosion'. The T-10 experimental study shows the dominant role of both m=1 and m=2 modes in the processes. The T-10 imaging system allows to reconstruct the m=2 perturbations, but only in the r/a<0.7 region, so the investigation of the minor and major disruptions was restricted by the high-qL density limit disruptions when the m=2 perturbation was placed well inside this region. (author) 6 refs., 2 figs