Thermionic current transport in a dielectric channel

The results are given of an experimental investigation of the transport of thermionic current in a dielectric channel. The results of an analysis of the current-voltage characteristics are used to demonstrate that the Child-Langmuir law does not extend to the case when the expansion of an electron flow due to the space charge effect is restricted by the channel walls. Furthermore, it is possible to obtain a value of the current density at the wall that is several orders of magnitude higher than its limiting value associated with the restriction with respect to the space charge.