论文标题
宇宙射线强度变化滞后黑子数：太阳磁场晚期打开的含义
Cosmic Ray Intensity Variation Lags Sunspot number: Implications of Late Opening of Solar Magnetic Field
论文作者
论文摘要
银河宇宙射线（GCR）是可能引起空间中宇航员关键健康问题的高能健康问题的高能颗粒，其强度落后于太阳点数（SSN）变化，大约一年。以前，该滞后归因于外向对流风和向内传播GCR的综合作用。但是，滞后幅度及其太阳周期依赖性仍然尚未完全了解（Ross＆Chaplin，2019）。通过研究太阳能表面磁场，我们发现地球磁场的来源 - 太阳上的开放磁通量，已经落后于SSN后面，然后再与太阳能风一起进入Heliosphere。奇数循环中的延迟比顺序偶数循环中的延迟更长。因此，我们建议GCR滞后主要是由于太阳能磁场在SSN方面的较晚开口，尽管太阳能对流和颗粒在Heliosphere中也很重要。我们进一步研究了来自太阳不同纬度的开放通量的起源，发现总开放通量是由经常发生冠状质量弹出的低纬度物质造成的，并且还显示出奇怪的循环模式。我们的发现挑战了现有的理论，并且可以作为载人深空探索任务的长期预测辐射剂量估计的物理基础。
Galactic cosmic rays (GCRs), the highly energetic particles that may raise critical health issues for astronauts in space, are modulated by solar activity with their intensity lagging behind the sunspot number (SSN) variation by about one year. Previously, this lag has been attributed to a combined effect of outward convecting solar wind and inward propagating GCRs. However, the lag's amplitude and its solar-cycle dependence are still not fully understood (Ross & Chaplin, 2019). By investigating the solar surface magnetic field, we find that the source of heliospheric magnetic field -- the open magnetic flux on the Sun, already lags behind SSN before it convects into heliosphere along with the solar wind. The delay during odd cycles is longer than that during sequential even cycles. Thus, we propose that the GCR lag is primarily due to the greatly late opening of the solar magnetic field with respect to SSN, though solar wind convection and particle transport in the heliosphere also matter. We further investigate the origin of the open flux from different latitudes of the Sun and found that the total open flux is significantly contributed by that from low latitudes where coronal mass ejections frequently occur and also show an odd-even cyclic pattern. Our findings challenge existing theories, and may serve as the physical basis of long-term forecasts radiation dose estimates for manned deep-space exploration missions.
