The ultrahigh-energy cosmic rays observed on the Earth are most likely accelerated in extra-Galactic sources. For the typical luminosities invoked for such sources, the electric current associated to the flux of cosmic rays that leave them is large. The associated plasma instabilities create magnetic fluctuations that can efficiently scatter particles. We argue that this phenomenon forces cosmic rays to be self-confined in the source proximity for energies E <Ecut, where Ecut≈107L442 /3 GeV for low background magnetic fields (B0≪nG ). For larger values of B0, cosmic rays are confined close to their sources for energies E <Ecut≈2 ×108λ10L441 /4B-101 /2 GeV , where B-10 is the field in units of 0.1 nG, λ10 is its coherence lengths in units of 10 Mpc, and L44 is the source luminosity in units of 1044 erg /s .
High-Energy Cosmic Ray Self-Confinement Close to Extra-Galactic Sources
BLASI P;
2015-01-01
Abstract
The ultrahigh-energy cosmic rays observed on the Earth are most likely accelerated in extra-Galactic sources. For the typical luminosities invoked for such sources, the electric current associated to the flux of cosmic rays that leave them is large. The associated plasma instabilities create magnetic fluctuations that can efficiently scatter particles. We argue that this phenomenon forces cosmic rays to be self-confined in the source proximity for energies EI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
