SPBSC-terpsichore bootstrap current benchmark for the low collisionality regime

The effects of the neoclassical bootstrap current have been investigated for nonaxisymmetric systems with different numerical and analytical tools. Fluid moment equations by Shaing et al [1] have been used at the National Institute for Fusion Science (Japan) to explore numerically with the SPBSC code the effects of bootstrap current in Large Helical Device (LHD, NIFS, Japan) plasmas [2]. In contrast to the LHD, the Wendelstein-7X (W7X, Greifswald, FRG) advanced stellarator has been optimised towards small Pfirsh-Schluter and small bootstrap currents [3]. The bootstrap current for the W7X has been calculated with a numerical drift kinetic solver DKES [4] and with global Monte Carlo simulation [5]. In this paper, we present the comparison between the SPBSC bootstrap current code results and new TERPSICHORE-BOOTSP routine recently developed at the CRPP (Switzerland), [6]. For the sake of simplicity, we take into account only zero radial electric field and for both ions and electrons, the same low collisionality (1/ν) regime, density and temperature profiles. For the benchmarking, we have chosen 3 typical cases corresponding to a symmetrical tokamak case JT-60 (Section 2), a heliotron/torsatron configuration the Large Helical Device (Section 3) and an advanced stellarator Wendelstein-7X case (Section 4) followed by a Summary.