Characterisation of induced vessel current during Mirnov probe calibration experiment in ADITYA-U tokamak

Abstract The stabilization of plasma column confined inside the vacuum vessel is supported by superposition of different vertical and horizontal magnetic field. These time varying magnetic field induces current in the vacuum vessel along with other neighbouring conducting structures. Magnetic probe results are greatly affected by induced vessel current in any nuclear-fusion experimental device. A central conductor is installed inside the ADITYA-U sectionalized segment of vacuum vessel for the calibration of Mirnov probes. The poloidal field distribution around the inner periphery of the vacuum vessel surface is investigated experimentally by using Mirnov probe garland. An analysis is described for the magnetic field at different sinusoidal frequencies and conductors at different radial and vertical locations. Mismatching in the measured magnetic field and applied current in the central conductor, measured at different frequencies hints at the presence of induced vessel current. Dissimilarity in the simulated and measured magnetic signal is computed to characterise the induced vessel current for different Mirnov probes. This technique may be useful to characterise the induced vessel current during ADITYA-U plasma discharges.