PX156 - J5 - natural sources of particles

natural radioactivity

$\beta$-decay in the earth:

• makes up about $2/3$ of the heat output at the surface $(\sim 40TW)$
• useful for tuning geological models of the earth's composition
• flux $={10}^6\nu s^{-1}c{m}^{-2}$
• energies $<3MeV$

cosmic ray showers

• very high energy hadrons and $\alpha$-particles
• generated by violent astrophysical sources such as active galactic nuclei (AGN), supernovae, colliding galaxies, etc
• do not know where they come from
• directions are scrambled by magnetic fields in the galaxy and extragalactic fields
• flux: $1m^{-2}{s}^{-1}\to 1k{m}^{-2}{s}^{-1}$
• energies: $1MeV\to {10}^{10}eV$

solar particles

• in addition to photons
  
• a lot of particles are emitted by the sun

solar wind

• plasma of charged particles emitted from the solar corona and streaming into space
• responsible for space weather
• flux $={10}^{9}c{m}^{-2}{s}^{-1}$
• energies $\simeq MeV$

solar neutrinos

• ${\nu }_e$ generated in the fusion process which power the sun
• flux $={10}^{1}0c{m}^{-2}{s}^{-1}$
• energies $=1-10MeV$