Computation of the Spitzer function in stellarators and tokamaks with finite collisionality Winfried Kernbichler, Gernot Kapper, Sergei V. Kasilov and Nikolai B. Marushchenko EPJ Web of Conferences, 87 (2015) 01006 Published online: 12 March 2015 DOI: 10.1051/epjconf/20158701006