Microbreakdowns in vacuum diode gaps with field-emission cathodes made of glass carbon

In this paper we perform experimental research results of micro breakdowns in diode gaps with the dimension less than 100 mkm. The main reason of micro breakdowns of gaps from 100mkm to 30 mkm is an explosion of nanoapexes on the cathode when the current density is about 1×10⁸ A/cm². In gaps less than 30 mkm the main initiator of breakdown is a warming-up and in some case also the anode material fusion in parts opposite the microapexes with power of electron flow with microapexes.