Vessel eddy current characteristics in SST-1 tokamak

Disruption forces on the tokamak wall with and without poloidal currents

“…The practical consequence is that the codes treating the vacuum vessel wall as a set of toroidal filaments (see examples in [11,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]) should be properly modified for calculations of the disruption forces and revision of the earlier evaluations.…”

“…It is known that, in fast events in JET, the electromechanical loads are predominately due to eddy currents [19]. Therefore, such model (often used in simulations, see [11,[31][32][33][34][35][36][37][38] and references therein) is applicable, at least, for estimating the forces at rapid disruptions. In other cases, it certainly covers an early stage of disruptions at which the disruption force can be large [11,33].…”

“…Here we refer to the fact that the wall is often represented as a set of circular conducting rings (called filaments) [11,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. The main consequence of the wall filamentation is that the induced currents are allowed in the toroidal direction only.…”

“…The unexpected findings in [11] can be considered as pointing to a previously unknown weak point in replacing the vacuum vessel wall by a set of toroidal filaments. Such substitution is used in several established codes (MAXFEA [11,26], TSC [23-25, 32, 37], CORSICA [27], PET [28,29], DINA [25,[30][31][32][33][34], CCS method code [35], see also [36] and [38]) providing the forecasts for existing and future tokamaks, including the ITER project. One can wonder when those data can be a reliable buttress for planning the strategy and when we need a revision with a full account of the wall currents.…”