Umstattd R J, Luginsland J W
Air Force Research Laboratory, Directed Energy Directorate, Kirtland Air Force Base, New Mexico 87117, USA.
Phys Rev Lett. 2001 Oct 1;87(14):145002. doi: 10.1103/PhysRevLett.87.145002. Epub 2001 Sep 17.
There is, at present, no analytic solution that extends Child-Langmuir space-charge-limited emission beyond 1D. Herein, we investigate the characteristics of planar diode electron emission in 2D space with the emphasis on the transition region between the beam and vacuum. Current density above that predicted by Child-Langmuir is observed near the beam edges in a 2D finite element, electrostatic ray-tracing code. The properties of these increased current density "wings" are examined and then discussed in terms of their applications to cathodes which have large reservoirs of free electrons.
