who first published it in 1911, or as the Child–Langmuir law, honoring as well Irving Langmuir, who discovered it independently and published in 1913. It was first used to give the space-charge-limited current in a vacuum diode with electrode spacing d. It can also be inverted to give the thickness of the Debye sheath as a function of the voltage drop by setting : . In recent years, the Child-Langmuir (CL) law have been revised as reported in two review papers. , See also Ambipolar diffusion Double layer (plasma), especially the section Current-carrying double layers formed by single, zero temperature beams List of plasma (physics) applications articles Footnotes Plasma physics Peter Debye