Database for recycling and penetration of neutral helium atoms in the boundary of a fusion plasma
Recently renewed attention has focused on the problem of helium ash accumulation in burning fusion plasmas, originating both from newly derived ignition criteria for point reactor models and from results of elaborate transport code calculations. Both approaches identify the repenetration of recycled helium atoms back into the plasma core as one of the critical processes. In order to facilitate numerical analysis of this problem and for reference purposes, newly derived relevant atomic and surface data in handy formats have been derived, similar to those routinely used in the analysis of the neutral hydrogen recycling process. In this report, a collisional-radiative atomic data package for the interaction of helium atoms with a thermalised electron background is provided, as well as a surface reflection model for helium atoms or ions incident onto stainless steel, graphite and tungsten target surfaces. This model comprises, as a function of incident energy and angle, the reflection probability and the fully 3-dimensional distribution in velocity space of the reflected particles.
Bibliographic Reference: Report: Jül-2605 EN (1992) 69 pp.
Availability: Available from Zentralbibliothek der Kernforschungsanlage Jülich GmbH, Postfach 1913, 5170 Jülich (DE)
Record Number: 199211065 / Last updated on: 1994-12-02
Original language: en
Available languages: en