Preliminary design of the AXUV diode measurements for the HL-2M tokamak

Abstract

• The HL-2 M tokamak is currently under final construction in SWIP. • Design and optimization of the AXUV diode arrays are performed for the HL-2 M tokamak. • A cooling system is designed to protect the detectors from high baking temperature. • Lay-out of lines of sight for AXUV bolometer on HL-2 M is proposed for a good coverage. Absolute extreme ultraviolet (AXUV) diode arrays are used to measure the plasma radiation for a wide spectral range in the fusion devices, providing valuable information about plasma radiated power and transport phenomena, especially during fast plasma events (such as plasma disruption and edge-localized mode). Design and optimization of the AXUV diode arrays are performed for the HL-2 M tokamak. 16-channel AXUV linear arrays are used as the diagnostic detectors, and a cooling system is designed to protect the detectors from high baking temperature. In order to meet the physical requirements, 176 lines of sight are designed within one toroidal section of the torus, and the geometrical arrangement of the arrays is optimized by coverage mapping and tomographic reconstruction test. Phantom simulation shows that the tomography methods can make reasonable reconstructions of the plasma emission profiles from the measurement of about 176 lines of sight. A 30 mm structure can be reproduced with 60 % accuracy. Therefore, the diagnostic will provide high spatially and temporally resolved plasma radiated power measurements in HL-2 M.