On Cosmic-Ray Production Efficiency at Realistic Supernova Remnant Shocks
説明
We demonstrate by using three-dimensional magnetohydrodynamics simulations that the cosmicray (CR) production efficiency at supernova remnants (SNRs) is over-predicted if it is based on proper motion measurements of Ha filaments in combination with Rankine-Hugoniot relations. Density fluctuations of upstream medium make shock waves oblique almost everywhere. For oblique shock, the kinetic energy of the shock wave is transferred into that of downstream turbulence as well as thermal energy related to the shock velocity component normal to the shock surface. Our synthetic observations shows that the apparent CR production efficiency as estimated from a lower downstream temperature, depends on the amplitude of density fluctuations of the upstream medium. They are roughly consistent with our analytical estimation of the efficiency. When the upstream medium has density fluctuations of typical diffuse interstellar medium, the apparent CR productions efficiency is observed as 10‐40 %.
収録刊行物
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- Proceedings of The 34th International Cosmic Ray Conference — PoS(ICRC2015)
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Proceedings of The 34th International Cosmic Ray Conference — PoS(ICRC2015) 485-, 2016-08-18
Sissa Medialab