Benchmarking of the mono-energetic transport coefficients—results from the International Collaboration on Neoclassical Transport in Stellarators (ICNTS)

• Published in: Nuclear fusion 2011-07, Vol.51 (7), p.076001
• Main Authors: Beidler, C.D, Allmaier, K, Isaev, M.Yu, Kasilov, S.V, Kernbichler, W, Leitold, G.O, Maaßberg, H, Mikkelsen, D.R, Murakami, S, Schmidt, M, Spong, D.A, Tribaldos, V, Wakasa, A
• Format: Article
• Language: English
• ISSN: 0029-5515; 1741-4326
• DOI: 10.1088/0029-5515/51/7/076001

Numerical results for the three mono-energetic transport coefficients required for a complete neoclassical description of stellarator plasmas have been benchmarked within an international collaboration. These transport coefficients are flux-surface-averaged moments of solutions to the linearized drift kinetic equation which have been determined using field-line-integration techniques, Monte Carlo simulations, a variational method employing Fourier–Legendre test functions and a finite-difference scheme. The benchmarking has been successfully carried out for past, present and future devices which represent different optimization strategies within the extensive configuration space available to stellarators. A qualitative comparison of the results with theoretical expectations for simple model fields is provided. The behaviour of the results for the mono-energetic radial and parallel transport coefficients can be largely understood from such theoretical considerations but the mono-energetic bootstrap current coefficient exhibits characteristics which have not been predicted.