Cosmic ray and solar energetic particle flux in paleomagnetospheres
Cosmic ray and solar energetic particle flux in paleomagnetospheres
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古磁层中的宇宙射线和太阳高能粒子通量
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
G. Voigt
中科院分区：
文献类型：
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作者：
A. Stadelmann;J. Vogt;K. Glassmeier;M. Kallenrode;G. Voigt
地磁场是阻止来自太阳和宇宙的高能粒子直接撞击地球表面的屏障的一部分。在地磁极性转变期间，地磁场强度显著降低，高能粒子更容易进入大气和地表。为了更详细地研究高能粒子进入古地磁层的通量，我们采用势场方法对古地磁层进行建模，该方法通过考虑核场的非零四极矩，推广了Voigt（1981）的参数化模型。我们特别研究了四极情况，因为地磁极性转变也具有非偶极贡献显著增加的特点。我们的模型被用作追踪这种古地磁层中的粒子轨迹和评估进入大气的高能粒子通量变化的工具。作为粒子跟踪方案的第一个应用，我们确定了不同古地磁层结构的截止纬度和影响区域。对于具有相同磁场强度或磁能的结构，影响区域非常相似。
The geomagnetic field is part of the shield prohibiting energetic particles of solar and cosmic origin directly hitting the Earth surface. During geomagnetic polarity transitions the geomagnetic field strength significantly decreases with energetic particles having a much better access to the atmosphere and surface. To study in more detail the flux of energetic particles into the paleomagnetosphere we use a potential field approach to model the paleomagnetosphere which generalizes the parametric model of Voigt (1981) by taking into account a non-zero quadrupole moment of the core field. We study in particular the quadrupolar situation as a geomagnetic polarity transition is also characterized by a significant increase of non-dipolar contributions. Our model is used as a tool for tracing particle trajectories in such paleomagnetospheres and to assess variations of high-energy particle fluxes into the atmosphere. As a first application of the particle tracing scheme we determine cutoff latitudes and impact areas for different paleomagnetospheric configurations. For configurations with equivalent magnetic field strength or magnetic energy the impact area is very similar.