THE RELATION BETWEEN POST-SHOCK TEMPERATURE, COSMIC-RAY PRESSURE, AND COSMIC-RAY ESCAPE FOR NON-RELATIVISTIC SHOCKS
THE RELATION BETWEEN POST-SHOCK TEMPERATURE, COSMIC-RAY PRESSURE, AND COSMIC-RAY ESCAPE FOR NON-RELATIVISTIC SHOCKS
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DOI：
10.1088/0004-637x/722/2/1727
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发表时间：
2010-08
期刊：
影响因子：
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通讯作者：
J. Vink;R. Yamazaki;E. Helder;K. Schure
中科院分区：
文献类型：
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作者：
J. Vink;R. Yamazaki;E. Helder;K. Schure
超新星遗迹（SNRs）被认为是银河系宇宙射线的主要来源。这需要至少5%的可用能量被转移到宇宙射线，这意味着SNR冲击下游的宇宙射线压力很高。最近，它已被证明，下游的温度在一些残余物是低的相比，测得的冲击波速度，这意味着额外的压力所支持的加速粒子存在。在这里，我们使用一个双流体热力学方法来推导激波后分数宇宙射线压力和激波后温度之间的关系，假设没有额外的加热以外的绝热加热的冲击前兆和所有的非绝热加热发生在亚激波。导出的关系表明，只有当相当大一部分的入射能流从系统中逃逸时，高分数宇宙射线压力才是可能的。最近，在SNR RCW 86中测量了激波的激波速度和下游质子温度。我们应用双流体的解决方案，这些测量，并发现，下游的分数宇宙射线压力至少为50%，宇宙射线能量通量逃逸至少为20%。一般来说，为了有5%的超新星能量进入加速宇宙线，平均来说，冲击后宇宙线压力需要达到30%，有效宇宙线绝热指数γcr = 4/3。
Supernova remnants (SNRs) are thought to be the dominant source of Galactic cosmic rays. This requires that at least 5% of the available energy is transferred to cosmic rays, implying a high cosmic-ray pressure downstream of SNR shocks. Recently, it has been shown that the downstream temperature in some remnants is low compared to the measured shock velocities, implying that additional pressure supported by accelerated particles is present. Here we use a two-fluid thermodynamic approach to derive the relation between post-shock fractional cosmic-ray pressure and post-shock temperature, assuming no additional heating beyond adiabatic heating in the shock precursor and with all non-adiabatic heating occurring at the subshock. The derived relations show that a high fractional cosmic-ray pressure is only possible if a substantial fraction of the incoming energy flux escapes from the system. Recently, a shock velocity and a downstream proton temperature were measured for a shock in the SNR RCW 86. We apply the two-fluid solutions to these measurements and find that the downstream fractional cosmic-ray pressure is at least 50% with a cosmic-ray energy flux escape of at least 20%. In general, in order to have 5% of the supernova energy to go into accelerating cosmic rays, on average the post-shock cosmic-ray pressure needs to be 30% for an effective cosmic-ray adiabatic index of γcr = 4/3.