Dependence of SOL widths on plasma current and density in NSTX H-mode plasmas

摘要

The dependence of various SOL widths on the line-averaged density (n_e and plasma current (l_p) for the quiescent H-mode plasmas with Type-V ELMs in the National Spherical Torus Experiment (NSTX) was investigated. It is found that the heat flux SOL width (λ_q), measured by the IR camera, is virtually insensitive to n_e and has a strong negative dependence on I_p. This insensitivity of λ_q to ne is consistent with the scaling law from JET H-mode plasmas that shows a very weak dependence on the upstream density. The electron temperature, ion saturation current density, electron density, and electron pressure decay lengths (λ_(Te), λ_(jsar),λ_(ne).and λ_(pe), respectively) measured by the probe showed that λ_(Te) and λ_(jsar) have strong negative dependence on I_p whereas λ_(ne). and λ_(pe) revealed only a little or no dependence. The dependence of λ_(Te) on I_p is consistent with the scaling law in the literature, while λ_(ne) and λ_(pe) dependence shows a different trend.