Askaryan radiation
The Askaryan radiation[1][2][3][4] also known as Askaryan effect is the phenomenon whereby a particle traveling faster than the phase velocity of light in a dense dielectric (such as salt, ice or the lunar regolith) produces a shower of secondary charged particles which contains a charge anisotropy and emits a cone of coherent radiation in the radio or microwave part of the electromagnetic spectrum. The signal is a result of the Cherenkov radiation from individual particles in the shower. Wavelengths greater than the extent of the shower interfere constructively and thus create a radio or microwave signal which is strongest at the Cherenkov angle. The effect is named after Gurgen Askaryan, a Soviet-Armenian physicist who postulated it in 1962.
The radiation was first observed experimentally in 2000, 38 years after its theoretical prediction. So far the effect has been observed in silica sand,[5] rock salt,[6] ice,[7] and Earth's atmosphere.[8]
The effect is of primary interest in using bulk matter to detect ultra-high energy
See also
References
- ^ Askar'yan, G. A. (1961). "Excess negative charge of an electron-photon shower and its coherent radio emission". Zh. Eksp. Teor. Fiz. 41 (1961): 616--618.
- ^ Askar'yan, G. A. (September 1965). "Coherent Radio Emission from Cosmic Showers in Air and in Dense Media" (PDF). Soviet Physics JETP. 21: 658.
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- S2CID 205247687.
- ^ "ANITA Project Overview". Archived from the original on 2015-09-24. Retrieved 2006-06-17.
- ^ "ARIANNA collaboration". Archived from the original on 2016-05-17. Retrieved 2014-11-28.
- ^ GLUE project
- ^ "NuMoon project". Archived from the original on 2009-09-17. Retrieved 2010-02-05.
- ^ LUNASKA project
- ^ RESUN project