SÉMINAIRE DU GRECO
"Modified Shocks and HE acceleration in SNR" |
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G. Morlino |
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I will give a brief outline of our understanding of the origin of cosmic rays and review the Fermi mechanism in the context of CR production in supernova remnants (SNRs). There is convincing evidence that SNR shocks can accelerate cosmic rays with high efficiency and if the acceleration is efficient, nonlinear effects will be important. These effects include a modification of the shock structure from the backpressure of CRs, an amplification of the ambient magnetic field above simple compression, and the production of a sizable flux of the highest energy CRs which escape upstream from the shock. I will show how nonlinear acceleration model can fit the electromagnetic radiation observed from some SNRs, and which are the open problems arising in this framework. |
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jeudi 30 avril 2009 - 11:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris |
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