Direct determination of the local ionospheric Hall conductance distribution from Two‐dimensional electric and magnetic field data: Application of the method using models of typical ionospheric electrodynamic situations
Direct determination of the local ionospheric Hall conductance distribution from Two‐dimensional electric and magnetic field data: Application of the method using models of typical ionospheric electrodynamic situations
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从二维电场和磁场数据直接确定局部电离层霍尔电导分布：使用典型电离层电动情况模型的方法的应用
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
O. Amm
中科院分区：
文献类型：
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作者：
O. Amm
本文用几种典型的电离层电动力学模型的输入数据，检验了一种从地面磁场和电离层电场观测值直接推导电离层霍尔电导分布的方法--特征线法的适用性。我们将表明，该方法的形式，一个完全自动的计算机算法是能够重现所有模拟的情况下，即二维东向电射流，哈朗不连续，欧米茄带，和向西行浪涌的WARTH分布。此外，我们将定量地表明，所隐含的模糊性的霍尔佩德森电导比的分布的必要假设只有很小的影响所获得的结果。我们还定量地证明，假设的垂直，直的地磁场线的方法的推导只会导致很小的误差，如果斜的情况下，但直的地磁场线是现实的。此外，我们回顾了该方法的一般理论，并讨论了一些额外的理论方面。特别是，我们将证明，孤立点E=0，但非零的doh.E与极值或鞍点的doh.H分布，并计算磁场扰动的电离层电流系统与倾斜，但直场对准电流直接低于电离层平面。该方法不需要静电情况;即，允许h ×E <$=0。
The applicability of a method to directly deduce the ionospheric Hall conductance distribution Σ H from ground magnetic and ionospheric electric field observations, here called method of characteristics, is tested by using input data from models of some typical ionospheric electrodynamic situations. We shall show that the method in the form of a fully automatical computer algorithm is able to reproduce well the Σ H distributions of all modeled situations, i.e. a two-dimensional eastward electrojet, a Harang discontinuity, an omega band, and a westward traveling surge. Furthermore, we will show quantitatively that the ambiguity implied by the necessary assumption of the distribution of the Hall to Pedersen conductance ratio has only a small effect on the results obtained. We also prove quantitatively that the assumption of vertical, straight geomagnetic field lines made in the derivation of the method leads only to very small errors if the case of oblique, but straight geomagnetic field lines is taken to be realistic. Moreover, we review the general theory of the method and discuss some additional theoretical aspects. In particular, we will show that isolated points with E=0, but nonvanishing ⊇ h .E are associated with extrema or saddle points of the Σ H distribution, and calculate the magnetic field disturbance of an ionospheric current system with oblique, but straight field-aligned currents directly below the ionospheric plane. The method does not require an electrostatic situation ; i.e., ⊇ h ×E¬=0 is allowed.