Investigation of radiation distribution in W7-X with an infrared video bolometer camera

Radiative cooling is one of the main energy loss channels in magnetically confined fusion plasmas. Hence, the radiation distribution and its emissivity are crucial aspects of heat transport, heat load mitigation, and plasma performance. An InfraRed Video Bolometer (IRVB) camera has been recently installed in W7-X to measure the radiated power, similarly to LHD [1].

The present contribution aims to describe the IRVB diagnostic and how it is employed to investigate the characteristics of radiated power in the island divertor [2]. First, the modeling of the IRVB diagnostic is detailed and the experimental results are discussed, finding strong magnetic field-aligned features and asymmetries connected with the target loads in different magnetic configurations. Then, the measurements are compared to EMC3-EIRENE results and other bolometer diagnostics, in an attempt to characterize the 3-D aspects of plasma radiation in W7-X.

[1] B. J. Peterson, Rev Sci Instrum 71, 2000

[2] D. Zhang, Phys Rev Lett 123, 2021