Modeling Solar Energetic Particle Transport near a Wavy Heliospheric Current Sheet
Modeling Solar Energetic Particle Transport near a Wavy Heliospheric Current Sheet
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DOI：
10.3847/1538-4357/aaa3fa
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发表时间：
2017-12
期刊：
影响因子：
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通讯作者：
M. Battarbee;S. Dalla;M. Marsh
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文献类型：
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作者：
M. Battarbee;S. Dalla;M. Marsh
了解太阳高能粒子（SEPs）从太阳加速点到行星际空间和地球的传输是预测空间天气的一个重要问题。行星际磁场（IMF）具有两种不同的极性和复杂的结构，控制着高能粒子的输运和漂移。本文首次分析了波浪形日球电流片（HCS）对SEP传播的影响。我们在太阳附近注入质子，并在弱散射的情况下，通过整合日光层内部的全三维轨迹来传播它们。我们模拟HCS的位置使用适合的中性线的磁场源表面地图（SSM）的基础上。我们映射1 Au质子过境点，这表明通过HCS在经度上的有效运输，这取决于相对于HCS的注入区域的位置。当HCS倾角在30° ~ 40 °之间时，我们发现IMF的A+和A−构型之间存在显著的质的差异，在前一种情况下，沿HCS的注量沿着更强，但在后一种情况下，粒子分布在更宽的纬度和纬度范围内。我们展示了波浪形电流片如何导致粒子注量的纵向周期性增强。我们表明，对于一个A+ IMF配置，波浪形HCS允许更多的质子减速比平坦的HCS。我们发现，由于电流片的径向漂移分量，A− IMF配置比A+ IMF配置导致更大的平均注量。
Understanding the transport of solar energetic particles (SEPs) from acceleration sites at the Sun into interplanetary space and to the Earth is an important question for forecasting space weather. The interplanetary magnetic field (IMF), with two distinct polarities and a complex structure, governs energetic particle transport and drifts. We analyze for the first time the effect of a wavy heliospheric current sheet (HCS) on the propagation of SEPs. We inject protons close to the Sun and propagate them by integrating fully 3D trajectories within the inner heliosphere in the presence of weak scattering. We model the HCS position using fits based on neutral lines of magnetic field source surface maps (SSMs). We map 1 au proton crossings, which show efficient transport in longitude via HCS, depending on the location of the injection region with respect to the HCS. For HCS tilt angles around 30°–40°, we find significant qualitative differences between A+ and A− configurations of the IMF, with stronger fluences along the HCS in the former case but with a distribution of particles across a wider range of longitudes and latitudes in the latter. We show how a wavy current sheet leads to longitudinally periodic enhancements in particle fluence. We show that for an A+ IMF configuration, a wavy HCS allows for more proton deceleration than a flat HCS. We find that A− IMF configurations result in larger average fluences than A+ IMF configurations, due to a radial drift component at the current sheet.