Survey of whistler mode chorus intensity at Jupiter
Survey of whistler mode chorus intensity at Jupiter
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DOI：
10.1002/2016ja022969
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发表时间：
2016-10
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影响因子：
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通讯作者：
J. Menietti;J. Groene;T. Averkamp;R. Horne;E. Woodfield;Y. Shprits;M. Pich;D. Gurnett
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文献类型：
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作者：
J. Menietti;J. Groene;T. Averkamp;R. Horne;E. Woodfield;Y. Shprits;M. Pich;D. Gurnett
惠斯勒模式的合唱发射在木星的电子加速和辐射带填充中起着重要的作用。在这项工作中，木星的合唱磁场强度水平（频率积分谱密度，PB）被全面地分类和参数化。所研究的合唱频率范围从较低的混合频率flh延伸到fceq/2和fceq/2 < f < 0.8 fceq，其中fceq为映射到磁赤道的回旋加速器频率。目标是获得磁场强度的量子化分布，用于随机建模工作。得到了磁等离子体波强度的参数拟合，包括PB与频率、纬度和L壳的关系。结果表明，木星合唱发生的概率和强度都高于土星，达到了在地球观测到的数值。木星的合唱在大多数当地时间被观测到，主要局限在8 < L < 15的范围内，在高密度的木卫一环外。最大的强度水平出现在白天；然而，在夜晚合唱的采样比在白天少得多。峰值强度发生在赤道附近，对磁纬度λ的依赖性较弱。我们得出结论，木星合唱的平均强度水平大约比地球低一个数量级。在更孤立的地区，其强度与在地球上观测到的强度相当。合唱发射的空间范围超出了先前的木星波粒电子加速全球扩散模型的假设。
Whistler mode chorus emission is important in the acceleration of electrons and filling of the radiation belts at Jupiter. In this work chorus magnetic intensity levels (frequency‐integrated spectral density, PB) at Jupiter are comprehensively binned and parameterized. The frequency range of chorus under study extends from the lower hybrid frequency, flh, to fceq/2 and fceq/2 < f < 0.8 fceq, where fceq is the cyclotron frequency mapped to the magnetic equator. The goal is to obtain a quantized distribution of magnetic intensity for use in stochastic modeling efforts. Parametric fits of magnetic plasma wave intensity are obtained, including PB versus frequency, latitude, and L shell. The results indicate that Jupiter chorus occurrence probability and intensity are higher than those at Saturn, reaching values observed at Earth. Jovian chorus is observed over most local times, confined primarily to the range 8 < L < 15, outside the high densities of the Io torus. The largest intensity levels are seen on the dayside; however, the sampling of chorus on the nightside is much less than on the dayside. Peak intensities occur near the equator with a weak dependence on magnetic latitude, λ. We conclude that Jovian chorus average intensity levels are approximately an order of magnitude lower than those at Earth. In more isolated regions the intensities are comparable to those observed at Earth. The spatial range of the chorus emissions extends beyond that assumed in previous Jovian global diffusive models of wave‐particle electron acceleration.