Position estimation of current-carrying filament using different magnetic sensors in ADITYA-U tokamak

ADITYA-U tokamak entails a major upgrade of installing a new divertor coil system to attempt shaped-plasma experiments. Such modification required the installation of a new circular vessel and a full set of magnetic diagnostics. Therefore, an in-situ calibration of the magnetic sensor is performed in ADITYA-U by installing a current-carrying filament inside the vacuum vessel. Different Mirnov sensors and other poloidal sensors like cosine and sine coils are found to be sensitive to the filament displacement and current at different frequencies. Moreover, results from multiple magnetic sensors are evaluated and compared for different locations of filament which are affected by the induced vessel current under varying experimental cases. Analysis based upon sensors response against filament displacement and its comparison with different type of magnetic sensors is performed and found to be in good agreement. Detailed results of calibration experiment for different cases are presented in this paper.