Design and test of magnetic probe for parallel wave-number measurement of lower hybrid waves in EAST

The design, simulation and test of the magnetic probe for the measurement of parallel wave-number spectrum of lower hybrid waves at 2.45GHz in EAST have been performed. Using the software COMSOL Multiphysics 5.2 based on finite element simulation, the size of the magnetic probe is simulated and optimized. Especially, some key dimensions that affect the coupling performance of the magnetic probe, such as dimension of the loop and the slit on the shield, the thickness of ceramic are determined. The test results show that the magnetic probe has good coupling performance for 2.45GHz lower hybrid waves and the ability for identifying wave polarization, which are in consistence with the theoretical simulation results. This work providesan important reference for the establishment of parallel wave-number measurement diagnosis system in EAST, which is critical for further high-density LHCD experiments.