Radiation distribution for shattered pellet injection experiment with AXUV array diagnostics in KSTAR

Shattered pellet injection (SPI) is the most promising technique for disruption mitigation in reactor-scale magnetic fusion devices such as ITER. For SPI experiments in KSTAR, an AXUV array diagnostic system has been developed to obtain the radiation distribution on the poloidal plane and in the toroidal direction during disruption. AXUV photodiodes enable faster radiation measurement than the sub-millisecond scale. A tomographic reconstruction code for poloidal AXUV arrays has been also developed and tested by synthetic images. For single SPI experiments in 2020, AXUV measurement with a tomography technique visualizes radiation images on the poloidal plane during disruptions. For single SPI, the radiation is highly peaked at the SPI position. A neon (Ne) concentration scan for single SPI shots shows that the radiation energy and current quench duration change significantly with the Ne quantity and saturate at high Ne concentration.