Application of the Abel-inversion method for the hard X-ray camera on the HL-2A tokamak

Abstract

Abstract The hard X-ray camera on the HL-2A tokamak has been used to study the behavior of energetic electrons in fusion plasma. In order to get precise hard X-ray emissivity information from the camera, a new hard X-ray emission profile reconstruction procedure based on the Abel-inversion method has been developed in the present paper. According to the verification results, the accuracy of the Abel-inverted profile depends on the accuracy of the interpolation and fitting processes. However, the error of the Abel-inverted profile is acceptable for the hard X-ray camera in general. For its applications, the procedure has been used to calculate the experimental local hard X-ray emission profiles. The calculation results show that the hard X-ray emission profiles were peaked at the center of the plasma, indicating the main energy of the lower hybrid wave was deposited at the center producing more energetic electrons than elsewhere. In addition, the calculation results can also indicate the confinement quality for energetic electrons, which can also be supported by statistical analyses for the line-integrated HXR emission profiles. The present paper lays a good foundation for the application of the hard X-ray camera on the HL-2A tokamak.