Are Anomalous Cosmic Rays the Main Contribution to the Low-Energy Galactic Cosmic Ray Spectrum?
Are Anomalous Cosmic Rays the Main Contribution to the Low-Energy Galactic Cosmic Ray Spectrum?
复制标题
异常宇宙线是低能银河系宇宙线光谱的主要贡献者吗？
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
Marius Potgieter
中科院分区：
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作者：
K. Scherer;H. Fichtner;Stefan Ferreira;I. Büsching;Marius Potgieter
虽然银河宇宙射线光谱的高能部分已被很好地观察到，但其能量低于约 1 GeV nucleon-1 的性质仍不清楚。最近利用航行者一号航天器在太阳风终止激波和日球层顶之间的日鞘中进行的原位测量进一步限制了低能量银河宇宙射线的局部星际光谱。我们在这里表明，它们还表明低能质子部分是如何在日光层局部形成以及在银河系整体形成的。与航行者一号到达激波之前的预期相比，测得的日鞘中异常宇宙射线通量出人意料地高，这可能是时间效应或由于超出终止激波的额外加速度所致。将这一发现与最近沉浸在不同星际环境中的天体模型结果相结合表明，太阳类恒星的天体异常宇宙射线通量可能比之前认为的高一百倍，因此，它们对星际光谱下端的总贡献可能是巨大的。
While the high-energy part of the Galactic cosmic ray spectrum is well observed, its nature at energies below about 1 GeV nucleon-1 is still not known well. Recent in situ measurements made with the Voyager 1 spacecraft in the heliosheath between the solar wind termination shock and the heliopause have added further constraints on the local interstellar spectrum of Galactic cosmic rays at low energies. We show here that they also suggest how the low-energy proton part is formed locally in the heliosphere and globally in the Galaxy. The measured flux of anomalous cosmic rays in the heliosheath is unexpectedly high compared to expectations before Voyager 1 reached the shock, which might be a temporal effect or due to an additional acceleration beyond the termination shock. Combining this finding with recent model results for astrospheres immersed in different interstellar environments shows that the astrospheric anomalous cosmic ray fluxes of solar-type stars can be a hundred times higher than thought earlier and, consequently, their total contribution to the lower end of the interstellar spectrum can be significant.