Simulation And Experiment For Eddy Current Studies On Toroidal Vessel Due To Simulated Plasma Instabilities

Abstract

In Tokamak, the plasma is con ned by the magnetic eld generated due to the plasma current as well as the external magnetic eld coils. Therefore, understanding of quench of the plasma current, such as disruption, has been one of the most critical issues in the Tokamaks. The plasma disruption instabilities and the large magnetic elds generate electromagnetic-type phenomena in transient conditions which lead to strong induced currents.The presence of a high magnetic eld due to the toroidal eld coils induces electromagnetic forces on interaction with the induced eddy currents. Eddy current experiments for discharge in coil and CS discharge are carried out. Eddy currents are measured by a Rogowski coil (RC), one of magnetic diagnostic (MD) sensors, which is used to diagnose induced currents in vessel during a plasma discharge. In Experiment two RCs are used, one was mounted on the outer surface of vessel and the other is mounted inner surface of the Vessel. The induced current can be obtained by subtracting simulated plasma current (which is measured by inner Rogowski coil) from the current measured by the Outer Rogowski coil mounted on vessel. The nite element analysis software used to carry out this project is ANSYS. ANSYS is the software that has been keenly programmed with many sorts of problem in electromagnetics. ANSYS gives more accurate and better solution for the actual geometry in existence. The project work involves the actual modeling and mapped meshing of the toroidal vessel geometry. Ansys Electromagnetic analysis gives the simulation results of the induced currents. The simulated results are compared with the induced currents obtained through experiment.