COSMIC RAY HEATING OF THE WARM IONIZED MEDIUM
COSMIC RAY HEATING OF THE WARM IONIZED MEDIUM
复制标题
宇宙射线加热暖电离介质
DOI：
10.1088/0004-637x/767/1/87
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
S. Peng Oh
中科院分区：
文献类型：
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作者：
Joshua Wiener;E. Zweibel;S. Peng Oh
对银河系热电离介质的线比的观测表明，光电离并不是唯一存在的加热机制。为了解释这种差异，额外的加热对气体密度的依赖性要弱于对冷却速率的依赖性。Reynolds等人认为湍流耗散或磁场重联是可能的热源。我们在这里研究了mhd波介导的宇宙射线加热作为补充热源的可行性。这一升温速率仅取决于气体密度，因为它与阿尔夫温速率呈线性关系，其为。我们表明，在适当的宇宙射线能量密度值上，宇宙射线加热可以是显著的。此外，这种加热对扰动是稳定的。这些结果应该也适用于其他星系中的热电离气体。
Observations of line ratios in the Milky Way's warm ionized medium suggest that photoionization is not the only heating mechanism present. For the additional heating to explain the discrepancy, it would have to have a weaker dependence on the gas density than the cooling rate, . Reynolds et al. suggested turbulent dissipation or magnetic field reconnection as possible heating sources. We investigate here the viability of MHD-wave mediated cosmic ray heating as a supplemental heating source. This heating rate depends on the gas density only through its linear dependence on the Alfvén speed, which goes as . We show that, scaled to appropriate values of cosmic ray energy density, cosmic ray heating can be significant. Furthermore, this heating is stable to perturbations. These results should also apply to warm ionized gas in other galaxies.