在河外激波模式中低高度云量的周期性能由cosmic ray可变性引起吗？
Can periodicity in low altitude cloud cover be induced by cosmic ray variability in the extragalactic shock model?
摘要：
高能宇宙射线（HECRs）的变化已被提出来解释62 My的陆地化石生物多样性的周期性。有人认为，我们的银河系向室女星系团的坠落可能会产生河外冲击，加速带电粒子，使地球暴露在高能宇宙射线（HECR）的通量中。太阳垂直于银道面的振荡可能会导致地球上的HECR通量的周期性为62 My，其幅度远远高于我们在太阳周期中看到的银河宇宙射线变化。这一机制可能解释了在过去500 My中观察到的陆地生物多样性的62 My周期性。除了对生命的直接影响外，高能回旋共振引起的空气簇射使大气层发生变化，导致大气化学和微物理过程发生变化，从而可能导致云的形成，包括低空云层。电离的增加改变了全球电路，这可能会通过微物理过程，如电清除和离子介导的成核作用，促进云凝结核（CCN）的形成，导致云量增加。这可能会增加太阳辐射，减少到达地面的太阳通量，从而降低全球温度。使用现有的模型，我们已经计算了在低海拔地区的大气电离增强暴露于HECR。我们使用一个保守的模型来估计低海拔云量的变化，从这个增加电离。
英文摘要：
Variation in high energy cosmic rays (HECRs) has been proposed to explain a 62 My periodicity in terrestrial fossil biodiversity. It has been suggested that the infall of our galaxy toward the Virgo cluster could generate an extragalactic shock, accelerating charged particles and exposing the earth to a flux of high energy cosmic rays (HECRs). The oscillation of the Sun perpendicular to the galactic plane could induce 62 My periodicity in the HECR flux on the Earth, with a magnitude much higher than the Galactic cosmic ray change we see in a solar cycle. This mechanism could potentially explain the observed 62 My periodicity in terrestrial biodiversity over the past 500 My. In addition to direct effects on life from secondaries, HECRs induced air showers ionize the atmosphere leading to changes in atmospheric chemistry and microphysical processes that can lead to cloud formation including low altitude cloud cover. An increase in ionization changes the global electric circuit which could enhance the formation of cloud condensation nuclei (CCN) through microphysical processes such as electroscavenging and ion mediated nucleation, leading to an increase in the cloud cover. This could increase the albedo and reduce the solar flux reaching the ground, reducing the global temperature. Using an existing model, we have calculated the enhancement in atmospheric ionization at low altitudes resulting from exposure to HECRs. We use a conservative model to estimate the change in low altitude cloud cover from this increased ionization.
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