Nottingham effect
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The Nottingham effect is a surface cooling and heating mechanism that occurs during field and thermionic electron emission.[1] which is named for physicist Wayne B. Nottingham who first described it during his research on thermionic electron emission.
Description
[edit]Notably, the effect can be either heating or cooling of the surface emitting the electrons,[1] depending upon the energy at which they are supplied; when the emission energy exceeds the Fermi energy of the electron supply, the emitted electron carries more energy away from the surface than is returned by the supply of a replacement electron, and the net heat flux from the Nottingham effect switches from positive to negative; this is known as the Nottingham Inversion Temperature[2] or simply Nottingham Temperature.
Along with Joule heating, the Nottingham effect contributes to the thermal equilibrium of electron emission systems, typically becoming the dominant contributor at very high emission current densities. It comes into play in the operation of field emission array cathodes and other devices that rely upon stimulating Fowler-Nordheim electron emission, usually at the apex of a sharp tip used to create a field enhancement effect. In extreme cases, the Nottingham Effect can heat the emitter tips to temperatures exceeding the melting point of the tip material, causing the tip to deform and emit material that may cause a vacuum arc; this is a significant failure mode for tip-based cathodes.[3][4]
References
[edit]- ^ a b Mofakhami, Darius (July 26, 2021). "Unveiling the Nottingham Inversion Instability during the thermo-field emission from refractory metal micro-protrusions". Nature Scientific Reports (nature.com). Retrieved October 20, 2024.
- ^ Behboodi, Zahra (July 28, 2023). "Nottingham Heating, Inversion Temperature and Joule Heating". Journal of Applied Mathematics and Physics. Retrieved October 20, 2024.
- ^ Kyritsakis, A. (March 20, 2017). "A generalized method for calculating electron emission and thermal evolution of metallic nanotips" (PDF). indico.cern.ch. Retrieved October 20, 2024.
- ^ Kyritsakis, A. (November 21, 2016). "A general computational method for electron emission and thermal effects in field emitting nanotips". arxiv.org. Retrieved October 20, 2024.