Liquid carbon surface during explosive emission

Electromigration occurences and its effects on metallic surfaces submitted to high electromagnetic field: A novel approach to breakdown in accelerators

“…Recently, Fursey and co-workers have discovered conditions where the apparition of explosive emission is impeded. It was observed on several metals as well as on carbon ( [98] and references therein). It seems to involve the evaporation of all the nanotips.…”

“…The origin of this phenomenon is unclear, although the most frequently proposed mechanism is pre-heating of the surface through field emission. Indeed, it is now possible to build liquid metal sources with high melting materials like graphite (Tm = 3800 K) or Tungsten (Tm = 3695 K) [97][98][99], by exposing the high melting point needle to an electron flow from a filament. In the case of W, heating of the surface in the range 2000-2300 K is sufficient to provide the appearance of nm size emitters [99], i.e.…”

A model study of the role of workfunction variations in cold field emission from microstructures with inclusion of field enhancements

“…A more complete and rigorous analysis would require the self-consistent and timedependent inclusion of electrothermal aspects. For example, the possibility of material vaporization from cathode tips has been reported in the literature [75,76]. From a theoretical standpoint, this is a dynamical energy-flow process with the electrons transferring energy gained from the field to the lattice via electron-phonon interactions.…”

Heating based model analysis for explosive emission initiation at metal cathodes

“…(d) Localized cathode heating can ultimately produce material ejection from cathode tips due to vaporization at high local temperatures, an aspect that has been observed in experiments. 19,20 (f) Material ejection dynamically alters the emitter shape and aspect ratio. This would probably change the field distribution at the surface, and could quench or smoothen nano-emissions at some locations, while initiating new localized sources of emission at different sites (e.g., along the rim of a newly formed crater).…”