Space-charge modulation in vacuum microdiodes at THz frequencies

Andreas Pedersen*, Andrei Manolescu, Ágúst Valfells

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)


We investigate the dynamics of a space-charge limited, photoinjected, electron beam in a microscopic vacuum diode. Because of the small nature of the system it is possible to conduct high-resolution simulations where the number of simulated particles is equal to the number of electrons within the system. In a series of simulations of molecular dynamics type, where electrons are treated as point charges, we address and analyze space-charge effects in a micrometer-scale vacuum diode. We have been able to reproduce breakup of a single pulse injected with a current density beyond the Child-Langmuir limit, and we find that continuous injection of current into the diode gap results in a well-defined train of electron bunches corresponding to THz frequency. A simple analytical explanation of this behavior is given.

Original languageEnglish
Article number175002
JournalPhysical Review Letters
Issue number17
Publication statusPublished - 27 Apr 2010


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