Comparing simulated and experimental spectral line splitting in visible spectroscopy diagnostics in the HL-2A tokamak

Abstract

We established Passive-Visible Spectroscopy Diagnostics (P-VSD) and Active-VSD (A-VSD) spectral splitting models for HL-2A Tokamak. Spectral splitting is due to the influence of electromagnetic (EM) fields on the spectral lines in VSD diagnostics. Zeeman splitting induced by the magnetic field (B) in P-VSD is used to distinguish reflection light overlap in the divertor. Stark splitting caused by the Lorentz electric field (ELorentz) from the Neutral Beam Injection (NBI) particle's interaction with the magnetic field (Vbeam×B) is used to measure the safety factor q in A-VSD. We give a comparison and error analysis by fitting the experimental spectra with the simulation results. The distinguishing of edge (Scrape-Off Layer, SOL, and divertor) Hydrogen/Deuterium (H/D) spectral lines and the q profile derived from the spectra provide a reference for the HL-2M VSD design.