Impurity transport has been studied in ohmic and neutral-beam-heated TFTR discharges by observation and numerical modeling of time evolutions of emissions from germanium injected using the laser-blowoff method. VUV spectral lines, the total radiated power, and soft X-ray intensities are compared with code predictions in which the impurity flux is assumed to have diffusive and convective terms. In plasmas with Ip = 1.4 MA and ne ≈ 2.5 × 1013 cm-3, no difference in transport between ohmic and beam-heated discharges is observed. At Ip = 0.7 MA and ne ≈ 1.0 × 1013 cm-3, a three-fold increase in the diffusion coefficient is found during beam heating.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Materials Science(all)
- Nuclear Energy and Engineering
- diffusion coefficients
- impurity dynamics
- impurity fluxes