Calculation method for eddy current effect of test mass in TianQin

Abstract

TianQin is proposed to detect gravitational wave signals at the frequency band of in space. Given that the residual acceleration noise of the test mass in TianQin is required to be below , all disturbing forces acting on the test mass should be estimated with the required precision. The magnetic force caused by eddy current is one of the error sources and should be treated seriously. In this paper, the eddy current effect is estimated by calculating the coupling between AC susceptibility and the applied ambient magnetic field. The proposed method demonstrates excellent agreement with direct calculations. The benefit of using the concept of AC susceptibility is that could be measured by precise experiment or calculated by FEM before launch, which improves the efficiency of calculation and increased the reliability and stability in space missions like TianQin.