J. Plasma Fusion Res. SERIES, Vol.l (1998) 222-225 Neoclassical Ambipolar Radial Electric Fields in H-lNF

A Monte Carlo neoclassical transport code has been developed to solve for the equilibrium ambi-polar radial electric field in the H-LNF Heliac. The code is applied to the conditions surrounding the Improved Confinement Mode transition in H-INF, and it is found that the transition is not inconsistent with neoclassical theory. The Monte Carlo code is also used to investigate the ion-electron root transi-tion. Positive radial electric fields are found, and it is suggested that the electron root may be easier to obtain in the H-INF than in a conventional stellarator of the same size. Keywords: stellarator, ambipolarity, radial electric field, neoclassical transport, H-mode, electron roo