SLOW DIFFUSION OF COSMIC RAYS AROUND A SUPERNOVA REMNANT
SLOW DIFFUSION OF COSMIC RAYS AROUND A SUPERNOVA REMNANT
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DOI：
10.1088/2041-8205/712/2/l153
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发表时间：
2010-02
期刊：
影响因子：
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通讯作者：
Y. Fujita;Y. Ohira;F. Takahara
中科院分区：
文献类型：
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作者：
Y. Fujita;Y. Ohira;F. Takahara
我们研究了在超新星遗迹（SNR）加速的宇宙射线质子逃逸。我们感兴趣的是，当它们离开激波附近时，它们在星际介质（ISM）中的传播，但当它们仍然接近SNR时，它们的能量密度高于平均ISM。利用Monte Carlo模拟，我们发现，如果ISM是高度电离的，能量为100TeV的宇宙射线在SNR附近激发的阿尔芬波的SNR本身的规模。因此，即使宇宙射线可以离开激波，波的散射也会阻止它们远离SNR。宇宙射线形成了一个缓慢膨胀的宇宙射线泡，它们在SNR周围停留了很长时间。这意味着宇宙射线实际上无法从SNR中逃逸，直到SNR演化的相当后期阶段。这与Fermi和H.E.S.S.意见。
We study the escape of cosmic-ray protons accelerated at a supernova remnant (SNR). We are interested in their propagation in the interstellar medium (ISM) after they leave the shock neighborhood where they are accelerated, but when they are still near the SNR with their energy density higher than that in the average ISM. Using Monte Carlo simulations, we found that the cosmic rays with energies of ≲ TeV excite Alfvén waves around the SNR on a scale of the SNR itself if the ISM is highly ionized. Thus, even if the cosmic rays can leave the shock, scattering by the waves prevents them from moving further away from the SNR. The cosmic rays form a slowly expanding cosmic-ray bubble, and they spend a long time around the SNR. This means that the cosmic rays cannot actually escape from the SNR until a fairly late stage of the SNR evolution. This is consistent with some results of Fermi and H.E.S.S. observations.