Effects of Leakage Neutral Particles on Shocks
Effects of Leakage Neutral Particles on Shocks
复制标题
泄漏中性粒子对冲击的影响
DOI：
10.1088/0004-637x/758/2/97
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
Yutaka Ohira
中科院分区：
文献类型：
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作者：
Satoru Katsuda;Yutaka Ohira;Koji Mori;Hiroshi Tsunemi;Hiroyuki Uchida;Katsuji Koyama;and Toru Tamagawa;大平豊;Kazunori Kohri;Eveline A. Helder;Yutaka Ohira;Yutaka Ohira
本文研究了中性粒子对传播到部分电离介质中的冲击波的影响。我们发现，当120 km s− 1< u sh< 3000 km s− 1（u sh是激波速度）时，大约10%的上游中性粒子从下游区域泄漏到上游区域。此外，我们还研究了泄漏中性粒子对激波上游结构和粒子加速度的影响。使用四流体近似（上游离子，上游中性粒子，泄漏中性粒子，和皮卡离子），我们提供了由于泄漏中性粒子的前体结构的解析解。结果表明，上游流动在前驱区被减速，冲击压缩比没有泄漏中性粒子时变小，但总压缩比没有变化。即使中性粒子的泄漏很小（占上游粒子总数的百分之几），这种较小的激波压缩比也可以解释年轻超新星遗迹的陡峭伽马射线谱。此外，泄漏的中性粒子可以放大磁场并加热上游区域。
In this paper, we investigate effects of neutral particles on shocks propagating into the partially ionized medium. We find that for 120 km s− 1< u sh< 3000 km s− 1 (u sh is the shock velocity), about 10% of upstream neutral particles leak into the upstream region from the downstream region. Moreover, we investigate how the leakage neutral particles affect the upstream structure of the shock and particle accelerations. Using four-fluid approximations (upstream ions, upstream neutral particles, leakage neutral particles, and pickup ions), we provide analytical solutions of the precursor structure due to leakage neutral particles. It is shown that the upstream flow is decelerated in the precursor region and the shock compression ratio becomes smaller than without leakage neutral particles, but the total compression ratio does not change. Even if leakage of neutral particles is small (a few percent of total upstream particles), this smaller compression ratio of the shock can explain steep gamma-ray spectra from young supernova remnants. Furthermore, leakage neutral particles could amplify the magnetic field and heat the upstream region.