A planar diode operating in the regime of limited electron emission

The current-voltage characteristic of a planar diode with a graphite explosive-emission cathode has been experimentally studied at the initial stage of electron current formation. An analytical expression has been obtained for the total area of discrete emitting centers in the cellular structure approximation, assuming that the number of such emitting centers operative during the current pulse formation is constant. It is shown that the electron current buildup for a cathode surface with discrete emitting centers is satisfactorily described by a modified Child–Langmuir formula with the form factor decreasing from $F$ = 6 to 1.