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 neutrinos. The Antarctic Impulse Transient Antenna (ANITA) experiment uses antennas attached to a balloon flying over Antarctica to detect the Askaryan radiation produced as cosmic neutrinos travel through the ice.[9][10] Several experiments have also used the Moon as a neutrino detector based on detection of the Askaryan radiation.[11][12][13][14]
See also
editReferences
edit- ^ 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. Bibcode:1965JETP...21..658A.
- ^ Hanson, Jordan C; Connolly, Amy L (2016). "Complex Analysis of Askaryan Radiation: A Fully Analytic Treatment including the LPM effect and Cascade Form Factor". Astroparticle Physics. 91: 75–89. arXiv:1605.04975. Bibcode:2017APh....91...75H. doi:10.1016/j.astropartphys.2017.03.008. S2CID 118850005.
- ^ Alvarez-Muñiz, Jaime; Romero-Wolf, Andrés; Zas, Enrique (2011-11-11). "Practical and accurate calculations of Askaryan radiation". Physical Review D. 84 (10): 103003. arXiv:1106.6283. Bibcode:2011PhRvD..84j3003A. doi:10.1103/PhysRevD.84.103003. ISSN 1550-7998. S2CID 119212570.
- ^ Saltzberg, David; Gorham, P; Walz, D; Field, C; Iverson, R; Odian, A; Resch, G; Schoessow, P; Williams, D (2001). "Observation of the Askaryan Effect: Coherent Microwave Cherenkov Emission from Charge Asymmetry in High Energy Particle Cascades". Physical Review Letters. 86 (13): 2802–5. arXiv:hep-ex/0011001. Bibcode:2001PhRvL..86.2802S. doi:10.1103/PhysRevLett.86.2802. PMID 11290043. S2CID 5600492.
- ^ Gorham, P. W.; Saltzberg, D.; Field, R. C.; Guillian, E.; Milinčić, R.; Miočinović, P.; Walz, D.; Williams, D. (2005-07-21). "Accelerator measurements of the Askaryan effect in rock salt: A roadmap toward teraton underground neutrino detectors". Physical Review D. 72 (2): 023002. arXiv:astro-ph/0412128. Bibcode:2005PhRvD..72b3002G. doi:10.1103/PhysRevD.72.023002. ISSN 1550-7998. OSTI 1442457. S2CID 53870487.
- ^ Gorham, P. W.; Barwick, S. W.; Beatty, J. J.; Besson, D. Z.; Binns, W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; Dowkontt, P. F.; DuVernois, M. A. (2007-10-25). "Observations of the Askaryan Effect in Ice". Physical Review Letters. 99 (17): 171101. arXiv:hep-ex/0611008. Bibcode:2007PhRvL..99q1101G. doi:10.1103/PhysRevLett.99.171101. ISSN 0031-9007. PMID 17995315. S2CID 16332031.
- ^ Buitink, Stijn; Corstanje, A.; Falcke, H; Hörandel, J. R; Huege, T; Nelles, A; Rachen, J. P; Rossetto, L; Schellart, P; Scholten, O; Ter Veen, S; Thoudam, S; Trinh, T. N. G; Anderson, J; Asgekar, A; Avruch, I. M; Bell, M. E; Bentum, M. J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Broderick, J. W; Brouw, W. N; Brüggen, M; Butcher, H. R; Carbone, D; Ciardi, B; Conway, J. E; et al. (2016). "A large light-mass component of cosmic rays at 1017–1017.5 electronvolts from radio observations". Nature. 531 (7592): 70–3. arXiv:1603.01594. Bibcode:2016Natur.531...70B. doi:10.1038/nature16976. PMID 26935696. 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