Measurements of the Magnetic Field Orientation in the Jovian Ionosphere
Measurements of the Magnetic Field Orientation in the Jovian Ionosphere
复制标题
木星电离层磁场方向的测量
DOI：
10.1029/ja083ia11p05245
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发表时间：
1978
影响因子：
5.2
通讯作者：
Fang
中科院分区：
文献类型：
--
作者：
R. Woo;Fang
本文分析了先锋号10号和11号掩星观测过程中观测到的S波段闪烁。我们发现，在碰撞占主导地位的低电离层中，电子密度不规则性是各向同性的，而在上电离层中，由于沿磁场的排列，它们是各向异性的。利用Rytov近似，导出了波在各向异性湍流介质中传播的对数振幅闪烁的频谱。结果表明，该谱在很大程度上取决于各向异性的方向，因此对于测量尚未被直接测量的区域的磁场方向是有用的。将这项新技术应用于先驱者10号和11号的观测，我们推导出了木星电离层磁场方向的第一次测量结果。
In this paper we analyze the S band scintillations observed during the Pioneer 10 and 11 occultation measurements of Jupiter. We find that while the electron density irregularities are isotropic in the collision-dominated lower ionosphere, they are anisotropic in the upper ionosphere because of alignment along the magnetic field. By using Rytov's approximation the frequency spectrum of the log-amplitude scintillations is derived for a wave propagating in an anisotropic turbulent medium. It is shown that the spectrum depends to a large extent on the direction of anisotropy and is therefore useful for measuring the orientation of the magnetic field in regions that have not yet been probed by direct measurements. Applying this new technique to the Pioneer 10 and 11 observations, we deduce the first measurements of magnetic field orientation in the ionosphere of Jupiter.