Dependence of secondary electron emission from carbon walls on the incident angle of electrons and charge-exchange neutrals emitted from plasma edges

Dependences of secondary electron emission of graphite walls bombarded by edge-plasma electrons and low-energy charge-exchange hydrogen-atoms on the angle of incidence are investigated, using a Monte Carlo simulation of the kinetic emission process. Very small increases of the secondary electron yield with oblique incidence are calculated for both cases. In addition, the secondary electron emission yield due to the backscattered particles is distinguished from that due to the trapped particles. It was found that the behavioural variation of the backscattered particles suppressed mainly the increase of the secondary electron yield with angle of incidence. (orig.)