Relation of Secondary Electron Emission to Snapover of Dielectric Surfaces Surrounding Biased Conductors in a Plasma
Bulletin of the American Physical Society
The current collected by a positively biased conductor, surrounded by a dielectric and immersed in a plasma, has been observed to increase dramatically when the conductor potential is raised above some threshold value (approximately 100-300 volts positive). The phenomenon termed "Snapover", is particularly relevant to the case of high-voltage solar arrays in Earth orbit. The fundamental physical process underlying the phenomenon is thought to be secondary electron emission (SEE) from the dielectric. Theoretical investigations and computer simulations have obtained results which are in excellent qualitative agreement with observation, though are somewhat lacking quantitatively. We offer an evaluation of our current understanding of the snapover phenomenon and will present results of a planned experiment which will systematically examine the importance of biasing rate, conducting material, insulating material, size and shape of the conductor, sample history, and condition of the dielectric surface (contamination and smoothness) to the threshold potential.
C. D. Thomson, JR Dennison, R.E. Davies, D.C. Ferguson, J.T. Galafaro and B.V. Vayner, “Secondary Electron Emission and the Snapover Effect,” Bull. Am. Phys. Soc. 44(1) (1999). American Physical Society Four Centennial Meeting, Atlanta , GA, March 22, 1999.