Eddy Current Analysis Of The Internal Thermal Shield Of HT-7U Tokamak

During plasma disruption,the variation of magnetic field will induce eddy current in the internal thermal shield of HT-7U Tokamak. The magnetic field produced by the eddy currents will influence both the equilibrium and the position & shape of the plasma. The magnetic field will also delay the penetration of outside magnetic field. The eddy currents will produce much eddy current losses,which play a very important role in the design of cooling system. In this paper,according to the structure of the internal thermal shield,the model of calculating the eddy currents when plasma disrupting is produced by the finite difference method. According to this model,the distribution and variation of the eddy currents on the internal thermal shield are calculated. The shape and the structure of the internal thermal shield are complicated. In this paper,a method which can be used to calculate the parameters which can influence the penetration of magnetic field is provided. This method can also be used for the calculation of metallic shields in any shape. The horizontal field and the eddy current losses produced by the eddy currents are also solved. This provides the theoretic foundation for engineering design and experimental running.