Cosmic Rays

In General > s.a. astrophysics.
* Idea: Particles of astrophysical (including the Sun and galactic sources) and cosmological origin arriving on Earth.
* History: 1912, First seen by Viktor Hess in a 5-km-high balloon flight; Named by Millikan; 1938, P Auger saw coincidences over distances > 1 km; Important for hep up to the 1950s, then accelerator data dominated; 1960s, E > 10²⁰ eV event detected by J Linsley; 1966, GZK prediction of 5 × 10¹⁹ eV cutoff; 1980s, renaissance in the form of search for he photons from pointlike astronomical sources (apparently up to 10³ TeV!), in the hope of getting undisturbed information on the source.
* Rates: At the surface we get about 1 muon/cm²/min; For primaries, the energy ranges from 10¹⁹ to 10¹⁹ eV, with a spectrum that drops sharply with E; We get about 1 event/m²/s at 10¹¹ eV, 1 event/m²/yr at 10¹⁶ eV (the "knee"), and 1 event/m²/cy at 10¹⁹ eV (the "ankle").
* Primary source: 1990, Not yet exactly known; Probably multiple origin, with lower energy (< 10¹⁵ eV) electrons and ions accelerated by supernova shocks in our galaxy, and more energetic ones extragalactic; 1995, First evidence of cosmic rays from supernova [@ Koyama et al Nat(95)nov]; 2007, High-energy cosmic rays originate in AGNs (probably accelerated by a stochastic process of multiple bounces off moving clouds carrying magnetic fields).
@ I: Ramaty et al PT(98)apr, ThSc(99)nov; Friedlander 00.
@ Intros, reviews: Ginzburg SPU(96); Baring ap/99-in; Dar et al ap/99/PRL [origin]; Ellis ap/00-in [and HEP]; Biermann & Sigl LNP(01)ap/02 [intro]; Moskalenko ap/04-in [propagation]; Hoerandel ap/05-in [measurements]; Parizot ap/05-in [whole spectrum]; Ferrari & Szuszkiewicz ap/06; Dar ap/06-in [origin] Hillas ap/06-in; De Rújula a0711-ln; Sommers & Westerhoff NJP-a0802; Gelmini a0903-in; issue NPPS(09)190.
@ General theory: Dar & De Rújula PRP(08) [single theory of non-solar cosmic rays].
@ From supernovae: Dar NCB(04)ap/04 [bipolar jets]; Berezhko & Voelk ApJL-a0704 [remnants]; Tatischeff a0804-in.
@ Sources, spectra: Dar & De Rújula PRP(08)hp/06 [single type of extrasolar source]; Mollerach a0902-in [anisotropy]; Abdo et FLAT PRL(09) + Winstein & Zurek Phy(09) [e⁺-e^– spectrum, 20 Gev–1 keV]; Abraham et PA a0907-in [spectrum], a0907-in [sources]; > s.a. high-energy cosmic rays [acceleration].
> Related topics: see astrophysical neutrinos; magnetism [particle acceleration]; matter phenomenology in quantum gravity; spacetime foam.

Specific Topics > s.a. statistics [non-extensive]; ultra-high energy cosmic rays.
* Anomalous cosmic rays: Accelerated at the termination shock, where the solar wind meets interstellar space.
* Composition: At a given energy, the ratio of protons to antiprotons is more than 10,000 to 1 (numbers are consistent with the levels of antiprotons expected from collisions between high-energy protons in cosmic rays and the nuclei of hydrogen and helium atoms in the interstellar medium), and electrons 100 to 1000 times less abundant than protons.
* Spectrum: The observed energy spectrum of cosmic rays on earth is not the source spectrum of these particles.
@ Spectrum, Tsallis statistics: Beck PhyA(04); Wlodarczyk & Wilk a0706-in [thermal sources].
@ Propagation in Milky Way galaxy: Erlykin et al APP(03)ap/02 [and ISM]; Strong et al ARNPS(07)ap; Huang & Pohl a0706-in [Monte Carlo].
@ Effects on Earth: Dar et al PRL(98) [life extinctions?]; Shaviv PRL(02) [climate and spiral-arm crossings]; Harrison & Stephenson PRA(06) [on clouds]; Melott et al a0804/PRD [atmospheric chemistry]; > s.a. earth [lightning].
@ Galactic vs extragalactic: Allard et al APP(07)ap/05; Aloisio et al PRD(08).
@ Positron and electron excess: Blasi PRL(09)-a0903; Bergström et al a0905 [dark-matter interpretation]; Pato et al a0905; Schubnell a0905-in; Grasso et al APP-a0905 [possible interpretations]; Cowsik & Burch a0906-in [nested-leaky-box model]; Sau et al HJ-a0906; Biermann et al PRL(09) [electrons and positrons from supernovae]; Shaviv PRL(09) [inhomogeneity of sources].
@ Composition: Kampert ap/02-in [chemistry]; Adriani et al PRL(09) + Swordy Phy(09) [antiprotons]; Abraham et Pierre Auger a0906-in.
@ Other topics: Catanese ap/99-in [Cerenkov]; Zweibel ApJ(03)ap/02 [B fields]; Lipari ap/03-in [and high-energy physics]; Fields & Prodanovic ApJ(05)ap/04 [history, from ⁶Li]; Alberghi et al PLB(04) [de Sitter vacua]; Kopenkin & Fujimoto PRD(06) [explanation of Centauro events].
> Special types: see astronomical objects [strangelets]; gamma rays.

Experiments and Other Phenomena > s.a. astronomy; astrophysical neutrinos; experimental projects [Pierre Auger].
* Projects: 2004, Auger project starts operating with a portion of its 1600 detectors, an array of water detectors to measure showers with E > 10¹⁹ eV; 2007, Auger project scheduled for completion; Extreme Universe Space Observatory in 2008?
@ Air showers: Anchordoqui et al AP(04)hp; Werner et al ap/04-in; Fargion ap/05-in [horizontal showers]; Dova ap/05-in; Drescher & Farrar APP(05)ap [AGASA]; Ahn & Cavaglià PRD(06) [black hole showers, simulations].
@ Balloon-borne: Cherry ap/05-in [towards higher E].
@ Other projects: Enqvist et al JPCS-ap/05 [EMMA]; Casolino et Pamela a0810-in, a0904-in [Pamela satellite experiment].
@ Other topics: Abbasi et Fly's Eye PRL(04) [observed flux]; Parker SA(03)mar [danger for space travelers]; Abdo et Milagro PRL(08) + Kampert Phy(08) [localized excess fluxes at 10 TeV].

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