cosmic rays
(CR)
(very-high-energy particles from beyond the solar system)
Cosmic rays are high energy particles,
typically with energies distributed around
0.3 GeV (4.8 × 10-11 joule),
but the highest energies have been
up to 3 × 1011 GeV.
The term cosmic ray was coined when detectors were developed
that demonstrate they continually fall on Earth,
and the term traditionally included photons.
However, common astrophysics usage has come to use EMR
terminology for such photons, and reserve the term cosmic ray
for other particles, including protons,
heavier nuclei (such as alpha particles),
electrons, with other particles such as neutrinos
sometimes included when they have similar energies.
They are theorized to be formed largely by supernovae.
Cosmic rays are continually arriving, i.e.,
as the cosmic ray background (CRB), but that phrase is not commonly
used perhaps because cosmic rays generally fit that description.
Some classes of cosmic-ray particles by kinetic energy (KE):
- solar cosmic rays or SCRs, under 10 GeV - at this energy, presumed to be from the Sun; basically the same as solar energetic particles.
- galactic cosmic rays or GCRs, i.e., 10 to 106 GeV - ubiquitous and presumed to be from within the Milky Way.
- extragalactic cosmic rays (occasionally EGCRs) - above the GCR maximum, presumed to be from beyond the Milky Way.
- VHE cosmic rays or VHECRs or very-high energy cosmic rays - above 100 GeV.
- UHE cosmic rays or UHECRs or ultra-high energy cosmic rays - above 1 EeV (109 GeV, not the same threshold used for ultra-high-energy gamma rays (UHEGR)).
- EE cosmic rays or EECRs or extreme energy cosmic rays - above the GZK limit, i.e., 50 million TeV or 5 × 1010 GeV.
The Oh-My-God Particle is an instance of the latter two.
A famous graph, the Swordy plot demonstrates that cosmic rays occur
basically with a power law spectrum over a wide range.
The distribution of particles approaching Earth (i.e., before the
effects of the atmosphere) decreases with energy, with roughly a
1-GeV particle per square meter per three hours down to roughly a
10-PeV (107 GeV) particle per square meter every four
months.
Cosmic ray astronomy makes use of space-based observatories
such as INTEGRAL, and ground detectors such as LOPES,
and Milagro. At high energies, the type of particle is often
not evident, merely the KE, and the abundances of proton
cosmic ray particles versus heavier nuclei or other particles at
particular energies is of research interest. There is something
of an assumption that they are protons, if there is no evidence to
the contrary.
(astrophysics,particles)
Further reading:
https://en.wikipedia.org/wiki/Cosmic_ray
https://en.wikipedia.org/wiki/Ultra-high-energy_cosmic_ray
https://en.wikipedia.org/wiki/Extragalactic_cosmic_ray
http://physics.stackexchange.com/questions/112966/is-it-known-what-causes-the-knee-in-the-observed-cosmic-ray-spectrum
http://www.hep.fsu.edu/~wahl/Quarknet/summer2015/lectures/CosmicRayIntrod.pdf
https://news.uchicago.edu/explainer/what-are-cosmic-rays
https://ui.adsabs.harvard.edu/abs/1926PA.....34..232M/abstract
Referenced by pages:
Advanced Composition Explorer (ACE)
air shower
airglow
alpha particle
AMS-02
anomalous cosmic rays (ACR)
antimatter
ARGO-YBJ Experiment
astrophysical neutrino
black hole (BH)
CASA-MIA
Cherenkov detector
cosmic background radiation (CBR)
dark matter detector
electron volt (eV)
electrostatic barrier
EUSO-SPB
Fenton Hill Observatory (FHO)
Fly's Eye
Forbush decrease
gamma rays (GR)
GRAPES-3
GZK limit
High Resolution Fly's Eye (HiRes)
high-energy astrophysics (HEA)
HZE ion
intensity interferometer
International Cometary Explorer (ICE)
ionizing radiation
LHAASO
lithium (Li)
localization
LOPES
Lunar Reconnaissance Orbiter (LRO)
multi-messenger astronomy (MMA)
neutrino observatory
neutron scattering
neutron spectrometer
nucleosynthesis
observational astronomy
Oh-My-God Particle
Orbiting Wide-angle Light Collectors (OWL)
PAMELA
Pierre Auger Observatory (PAO)
POEMMA
power law
proton
radioactive dating
relativistic astrophysics
scintillator
solar energetic particle (SEP)
source
Swordy plot
tau neutrino (ντ)
TD-1A
Telescope Array Project (TA)
Tunka experiment
ultra-high-energy gamma rays (UHEGR)
Ulysses
Van Allen belts
VHE
Voyager
weathering
Index