Electron bunching from a dc-biased, single-surface multipactor with realistically broad energy spectrum and emission angle of secondary electrons

We studied the influences of wide energy spectrum and emission angle of secondary electrons on electron bunching from a dc-biased single surface multipactor. In our previous study of the same system, an ideally narrow energy spread of secondary electrons without emission angle was used in the analysis of the electron trajectory [M. S. Hur, J.-I. Kim, G.-J. Kim, and S.-G. Jeon, Phys. Plasmas 18, 033103 (2011) and S.-G. Jeon, J.-I. Kim, S.-T. Han, S.-S. Jung, and J. U. Kim, Phys. Plasmas 16, 073101 (2009)]. In this paper, we investigated the cases with realistic energy spectrum, which is featured by a wide energy spread and significant emission angle. To theoretically approach the matter of emission angle, we employed a concept of effective longitudinal velocity distribution. The theoretical results are verified by particle-in-cell (PIC) simulations. We also studied the electron bunching from a copper by PIC simulations, where we observed stable electron bunches with bunch width of approximately 80 mu m.open3