Dispersion of electrostatic waves in the Io plasma torus and derived electron temperature
Dispersion of electrostatic waves in the Io plasma torus and derived electron temperature
复制标题
Io 等离子体环中静电波的色散和导出的电子温度
DOI：
10.1029/95ja02299
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发表时间：
1995
影响因子：
--
通讯作者：
S. Hoang
中科院分区：
文献类型：
--
作者：
M. Moncuquet;N. Meyer‐Vernet;S. Hoang
我们提出了一个详细的分析的无线电频谱的一组期间获得的宇宙飞船通过外部的木卫一等离子体环（在108 Rj）。由于ESTA是第一个探索远离赤道的环面的航天器，并且机载等离子体分析仪被关闭，这些波数据是唯一提供赤道区域以外的原位等离子体诊断的数据。我们在这里提出两个主要结果。首先，通过比较观察到的电子回旋谐波之间的测量信号的自旋调制的静电波传播大致垂直于B的理论调制，我们推导出这些波的实验色散曲线。这些曲线与准热等离子体中的伯恩斯坦色散曲线非常相似。其次，通过拟合这些理论色散关系的实验，我们能够推导出约20%的不确定性时，密度独立测量的核心电子温度。否则，我们可以得到密度和温度的粗略估计。相关文献（N. Meyer-Vernet，M. Moncuquet和S. Hoang，1995）。
We present a detailed analysis of the set of radio spectra acquired during the Ulysses spacecraft passage through the outer part of the Io plasma torus (at ∼8 R j ). Since Ulysses is the first spacecraft to explore the torus far from the equator and the onboard plasma analyzers were shut off, these wave data are the only ones providing an in situ plasma diagnostics outside the equatorial region. We present here two main results. First, by comparing the observed spin modulation of the signal measured between electron gyroharmonics to the theoretical modulation for electrostatic waves propagating roughly normal to B, we deduce experimental dispersion curves for these waves. These curves are very similar to Bernstein dispersion curves in a quasi-thermal plasma. Second, by fitting these theoretical dispersion relations to the experimental ones, we are able to deduce the core electron temperature with about 20% uncertainty when the density is measured independently. Otherwise, we can get a rough evaluation of both the density and the temperature. The corresponding latitudinal variation of these parameters is analyzed in a related paper (N. Meyer-Vernet, M. Moncuquet, and S. Hoang, 1995).