Blasi, P.P.BlasiAMATO, ElenaElenaAMATOD'Angelo, M.M.D'Angelo2020-03-272020-03-2720151824-8039http://hdl.handle.net/20.500.12386/23624Most models of the origin of ultra high energy cosmic rays rely on the existence of luminous extragalactic sources. Cosmic rays escaping the galaxy where the source is located produce a suf- ficiently large electric current to justify the investigation of plasma instabilities induced by such current. Most interesting is the excitation of modes that lead to production of magnetic perturba- tions that may scatter particles thereby hindering their escape, or at least changing the propagation mode of escaping cosmic rays. We argue that self-generation of waves may force cosmic rays to be confined in the source proximity for energies $E<10^7\ L_{44}^{23}$ GeV for low background magnetic fields ($B_0 \ll$ nG). For larger values of $B_0$, cosmic rays are confined close to their sources for energies $E < 2 \times 10^8\ \lambda_{10}\ L_{44}^{1/4} B_{-10}^{1/2}$ GeV, where $B_{-10}$ is the field in units of 0.1 nG, $\lambda_{10}$ is its coherence length in units of 10 Mpc and $L_{44}$ is the source luminosity in units of $10^{44}$ erg/s.ELETTRONICOenConference paperhttps://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=2362015ICRC...34..505BFIS/05 - ASTRONOMIA E ASTROFISICAScienze Fisiche Settori ERC (ERC) di riferimento::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation::PE9_10 High energy and particle astronomy – X-rays, cosmic rays, gamma rays, neutrinos