Numerical simulation of the atmospheric ionization and the generation of cosmogenic nuclides for different topologies of the geomagnetic field

来自太阳和银河系的宇宙射线部分被两个过滤器——磁层和大气层——从地球表面屏蔽掉。众所周知，地球磁场在不同的时间尺度上变化很大。磁场及其变异性源于地核内部的磁流体动力发电机过程，这种变异性在伴随磁场强度急剧下降的磁场倒转中表现得最为明显。地磁场的变化改变了高能粒子进入低层大气的途径，改变了宇宙核素（如10Be和14C）的产生以及中层大气引起的电离。在这项研究中，我们将建立一个结合粒子在不同强度和拓扑的地磁场中的传播以及粒子与大气的相互作用的模型，以确定(a)共生核素的产生和(b)不同拓扑/强度的地磁场中高能粒子引起的电离。这项研究的结果可以用作发电机模型的附加测试，也可以作为确定不同地磁场状态下大气变化（如臭氧含量或全球环流）的输入。

Cosmics rays of solar and galactic origin partly are screened off from the Earth's surface by two filters, the magnetosphere and the atmosphere. The terrestrial magnetic field is known to be quite variable on different time scales. The field and its variability, which is most obvious in magnetic field reversals accompanied by dramatic decrease in the magnetic field strength, originates in a magnetohydrodynamic dynamo process inside Earth's core. Changes in the geomagnetic field modify the access of energetic particles to the lower atmosphere, altering the generation of cosmogenic nuclides such as 10Be and 14C as well as the ionization of the mid-atmosphere caused. In this study we will develop a model combining the particle propagation in a geomagnetic field of different strenghts and topologies and the particle interaction with the atmosphere to determine (a) the generation of cocmogenic nuclides and (b) the ionization caused by the energetic particles for different topologies/strengths of the geomagnetic field. The results of this study can be used as additional tests for dynamo models and as an input to determine atmospheric changes, such as the ozone content or the global circuit, for different states of the geomagnetic field.