Askaryan effect
From Wikipedia, the free encyclopedia
The Askaryan effect describes a phenomenon, similar to the Cerenkov effect, whereby a particle travelling faster than the speed of light in a dense radiotransparent medium such as salt, ice or the lunar regolith produces a shower of secondary charged particles which contain a charge anisotropy and thus emits a cone of coherent radiation in the radio or microwave part of the electromagnetic spectrum. So far the effect has been observed in silica sand [1], rock salt [2], and ice [3] and is of primary interest in using bulk matter to detect ultra-high energy neutrinos. The effect is named after its postulator, physicist Gurgen Askaryan (1928-1997).
[edit] ANITA
The (Antarctic Impulsive Transient Antenna) ANITA experiment is to be the first experiment to identify high energy neutrinos created by collisions between cosmic rays and the cosmic microwave photons that pervade the Universe, a source of neutrinos that creates an opportunity to study the laws of high-energy physics. This experiment exploits the Askaryan Effect. At these energies, neutrino collisions with matter could produce micro-black holes, or other exotic manifestations of theories that attempt to unify all forces of Nature.[4] The balloon-borne payload will circle the continent of Antarctica at ~35,000 meters, scanning the vast expanses of ice for telltale pulses of radio emission generated by the neutrino collisions. This project is as of June 2006 being tested at the Stanford Linear Accelerator Center[5].
