Physics of electron emission from metal-dielectric cathodes

The present paper gives a description of the metal-dielectric cathode operation. There is an explosive electron emission on the cathodes, that occurs through explosions of the metal micro protrusions at so-called triple points (metal-dielectric-vacuum). The current of a vacuum discharge over dielectric surface plays its initiating part. Such a mechanism of emission is operating in low-voltage ferroelectric cathodes, in cathodes of long service in high-power pulse repetitive accelerators as well as in the cathodes used in focusing high power electron beams.