Plasma-Surface Interaction in Presence of Intense Electron Emission from Walls

The plasma-surface interaction in presence of strong thermionic or secondary electron emission has been studied theoretically and experimentally both as a basic phenomenon and in relation to numerous plasma applications such as, divertor plasma, particle accelerators, surface discharges, plasma thrusters and plasma processing [1-3]. Secondary electron emission (SEE) from walls can be induced by electron or ion impact. The SEE can greatly alter the plasma-wall interaction and modify the whole structure of the plasma and its stability. A review of present theoretical models and experimental methods of investigating emission properties of different materials will be given. We also review a recently proposed effect that the reflectivity of very low energy electrons from solid surface approaches unity in the limit of zero electron energy [2]. We report on recent experimental and particle-in-cell simulation studies on plasma-surface interaction in presence of electron emission [3,4]. \\[4pt] [1] J. Cazaux. J. Appl. Phys. 111 064903 (2012). [2] R. Cimino, I.R. Collins. Appl. Surface Scie. \textbf{235}, 231 (2004). [3] Y. Raitses, et al, IEEE Trans. on Plasma Scie. \textbf{39}, 995 (2011). [4] M. D. Campanell, et al, Phys. Rev. Lett. \textbf{108}, 235001 and 255001 (2012).