Neoclassical and Anomalous Transport Analysis of Helical Reactor Plasmas

The plasma parameters of the standard LHD (Large Helical Device)-type helical reactor (LHR-S) are estimated using zero-dimensional (zero-D) model with radial parabolic profile correction and 2.0-D (1-D transport / 3-D equilibrium) analysis with neoclassical and anomalous transport models. Zero-dimensional analysis using global confinement scaling laws including “new LHD modified ” scaling laws clarifies the required D-T ignition machine scale, magnetic field and confinement improvement factor. The 2.0-D analysis for LHR-S with 450 MW alpha particle power clarifies the feedback burn control behavior and radial profiles of ignited steady-state plasmas. In the case of low-beta inward-shifted configuration and smaller ion anomalous loss, the plasma can be ignited with the major radius R of ~15m (4.2 times larger than LHD) and the magnetic field strength B of ~5T. The real high beta configuration leads to the increase of effective helical ripple, and the required density regime becomes rather high. If we add the ion anomalous transport, the access to ignition becomes difficult and the thermal instability is found to be excited due to required high-density low-temperature conditions. Keywords: neoclassical transport, confinement scaling laws, effective helical ripple, burn control, helical system, DT ignition