Initial Experimental Results of Three-Dimensional Plasma Structure Reconstructed from Seven Independent X-Ray Images on RELAX

Abstract

In this study, we demonstrated the principle underlying the three-dimensional (3D) reconstruction of plasma structure by using a soft X-ray camera with multiple pinholes. Time evolutions of seven independent soft X-ray images were captured by the camera. The obtained data were used to reconstruct a 3D soft X-ray emission profile in the reversed-field pinch produced in the RELAX machine, which appeared to be consistent with the forecast in our feasibility study. c

First Experimental Monitoring of the Three-Dimensional Structure of Toroidal Plasmas Using Multiple Soft X-Ray Imaging Techniques

“…5. As described in a previous report [6], the FB series' range of modes using the 3D reconstruction was set to 0 ≤ m ≤ 2, −8 ≤ n ≤ 8, and 1 ≤ k ≤ 3, where the parameters m, n, and k are the poloidal, toroidal, and radial mode numbers, respectively. The coefficients of the FB series were calculated by the Ridge and Lasso regressions, as explained in Ref.…”

“…In this study, a 3D tomography method was applied using a "multiple-pinhole camera," as described in a feasibility study [5] and preliminary report [6], to detect 3D structures in RFP plasmas. The camera was used to monitor plasma shapes by detecting bremsstrahlung emission in the SXR range, which depends on plasma densities and electron temperatures [7].…”