Ion Temperature Characteristics of Upgraded DIVA

The radial profile and scaling law of ion temperature were examined on hydrogen plasmas in the DIVA tokamak device with its toroidal magnetic field upgraded from 10 to 20 kG. The radial profile of ion temperature was measured from the Doppler broadening of various impurity lines in vacuum uv and ultraviolet regions which were experimentally confirmed to emit from a localized position in the minor cross-section and from the energy spectrum of charge-exchanged fast hydrogen-atoms. The radial profiles obtained from these two methods were in agreement in the inner region (( r / a )\({\lesssim}0.6\) with the minor radius a of the device). The central ion temperatures were investigated in the wide parameter ranges: toroidal magnetic fields 6≦ B _t ≦20 kG; plasma currents, 10≦ I _p ≦48 kA; and averaged electron densities \(0.6{\leqq}\overline n_{\text{e}}{\leqq}3.8\times10^{13}\) cm ^-3 . The obtained central ion temperatures were found to be in good agreement with Artsimovich's scaling law.