Sensitivity of measured external magnetic field on cross-section of toroidal current column in ADITYA-U tokamak

The change of external magnetic field due a toroidal current column with the variation of its circular cross-section is studied using experimental measurements for ADITYA Upgrade (ADITYA-U) tokamak plasma. Due to any toroidal current column, the poloidal magnetic field, outside the current column, at all points over the poloidal periphery of a circle of a particular radius in the azimuthal plane, is found to be sensitive to its cross-sectional area, depending on the location of the subject point, and it is already predicted by numerical approaches, except at a loci of points at some particular angle 6 . Consequently, the Angle of Invariance in Change in poloidal magnetic field intensity, H (AICH) is empirically confirmed to fall within the expected angular range as predicted by numerical results. The outcomes are inevitable for any toroidal current of circular cross-section, irrespective of its magnitude and geometry.