Emission and postemission of charged particles in vacuum at low values of an external electric field

It is known, that the presence of oxide films and nonmetallic inclusions on a high-voltage electrode surface considerably reduce a vacuum gap electric strength. One of this phenomenon causes is electric charge occurrence in them, which one increases an external electric field strength. The charged particles postemission existence after external voltage switching-off is explained by such charge influence. In this report the experiment data, in which one the increase of an electric charge on an electrode surface after external voltage switching-off was watched, are represented. It is demonstrated, that at low external field strength it is impossible to explain this phenomenon by a field emission processes. Prebreakdown currents appearance and behavior of a charge in nonmetallic films mechanisms are considered by processes in pores or pore typed defects, i.e. by poroemission processes.