Storm-time ring current: model-dependent results
Storm-time ring current: model-dependent results
复制标题
风暴时间环电流：模型相关结果
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
T. Pulkkinen
中科院分区：
文献类型：
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作者：
N. Ganushkina;M. Liemohn;T. Pulkkinen
抽象。本文的主要观点是调查有多少建模环电流依赖于磁场和电场的表示和模拟中使用的边界条件。模拟了两次风暴事件，一次是1997年11月6日至7日的中等强度（SymH最小值为−120 nT），另一次是1999年10月21日至22日的强烈风暴（SymH最小值为−230 nT）。一个相当简单的环电流模型，即内磁层粒子传输和加速模型（IMPTAM），以使结果最明显。采用了四种不同的磁场和两种电场表示法以及四种边界条件。我们发现，不同的组合的磁场和电场的配置和边界条件的结果非常不同的建模环电流，因此，基于模拟结果的物理结论可以显着不同。6.6 RE之外的时间相关边界使得有可能考虑过渡区域（偶极和拉伸场线之间）中的粒子，在该区域形成部分环电流和近地尾电流。由于电流是在非偶极磁场区计算的，因此用Biot-Savart定律代替Dessler-Parker-Sckopke（DPS）关系式计算模型SymH* 可以得到更大更真实的数值。因此，边界位置和SymH* 计算方法是环电流数据模型比较的关键重要性，以正确解释。
Abstract. The main point of the paper is to investigate how much the modeled ring current depends on the representations of magnetic and electric fields and boundary conditions used in simulations. Two storm events, one moderate (SymH minimum of −120 nT) on 6–7 November 1997 and one intense (SymH minimum of −230 nT) on 21–22 October 1999, are modeled. A rather simple ring current model is employed, namely, the Inner Magnetosphere Particle Transport and Acceleration model (IMPTAM), in order to make the results most evident. Four different magnetic field and two electric field representations and four boundary conditions are used. We find that different combinations of the magnetic and electric field configurations and boundary conditions result in very different modeled ring current, and, therefore, the physical conclusions based on simulation results can differ significantly. A time-dependent boundary outside of 6.6 R E gives a possibility to take into account the particles in the transition region (between dipole and stretched field lines) forming partial ring current and near-Earth tail current in that region. Calculating the model SymH* by Biot-Savart's law instead of the widely used Dessler-Parker-Sckopke (DPS) relation gives larger and more realistic values, since the currents are calculated in the regions with nondipolar magnetic field. Therefore, the boundary location and the method of SymH* calculation are of key importance for ring current data-model comparisons to be correctly interpreted.