Plasma Current Distribution Clausole campione

Plasma Current Distribution. The aforementioned analyses were made assuming a simple plasma model, composed of six filaments reproducing the magnetic field of reference plasma with a current of 5.5 MA. A more refined reference plasma model, composed of more than 3000 current filaments but with the same βp and lP reference values, has been used with the aim of evaluating the effect of the plasma discretization on the resulting external coil overcurrent. The results for the external superconducting magnets, shown in the third column of Table 2.5, do not wander more than 2% of the nominal current in respect to the ones obtained with the six filament model. It is therefore clear that the effect of realistic current profile is negligible for this study. On the contrary a significant difference is obtained in the HC coils, due to the fact that these are internal coils and are more affected by plasma current variation than external ones, since they are not shielded by the presence of low resistance vessel. 6 filaments Reference Increased flux Increased lP A different initial magnetic field created by a different plasma current distribution at the time of disruption could lead to variations of the over-current values both in the HC in-vessel coils and in the superconducting coils, being changed the mutual coupling between coils and plasma. In order to investigate this possibility, a number of plasma scenarios has been considered among the possible plasma equilibrium conditions with 5.5 MA current. Several equilibrium plasma current distributions have been simulated with the TOSCA code [16] considering different possible combinations of lP, βN and ψC, obtaining precise plasma current distributions with more than 3000 current filaments. The resulting detailed plasma models have been inserted in the zero-dimensional poloidal circuit model for simulating a disruption with plasma in a fixed position. The results, reported in columns 4 and 5 of Table 2.5 for two plasma equilibria characterized respectively by an increase in flux consumption (lP = 4.6 μH, βN = 1.23 and ψC = 21.4 Wb) and an increase of lP (lP = 5.06 μH, βN = 1.35 and ψC = 18.8 Wb) respect with the reference equilibrium, show that with the considered initial plasma current distributions only negligible variations are observed both in superconducting and in-vessel coil overcurrents, meaning that the variation of plasma parameters as flux consumption and lP has negligible effect on coil overcurrent.