Identification of Jupiter’s magnetic equator through H3+ ionospheric emission
Identification of Jupiter’s magnetic equator through H3+ ionospheric emission
复制标题
DOI：
10.1038/s41550-018-0523-z
复制
发表时间：
2018-07
期刊：
影响因子：
14.1
通讯作者：
T. Stallard;A. Burrell;H. Melin;L. Fletcher;S. Miller;L. Moore;J. O’Donoghue;J. Connerney;T. Satoh;Rosie E Johnson
中科院分区：
文献类型：
--
作者：
T. Stallard;A. Burrell;H. Melin;L. Fletcher;S. Miller;L. Moore;J. O’Donoghue;J. Connerney;T. Satoh;Rosie E Johnson
我们对木星磁场的了解是通过宇宙飞船在距离bbbb1.8 j的测量和极光的图像，，，，，-的结合而发展起来的。这些模型都与木星偶极磁矩的强度和方向一致，但由于高阶磁矩随着与行星的距离而衰减得更强烈，过去的航天器测量无法轻易地解决它们。在过去的两年里，朱诺号任务已经在离木星非常近的地方进行了测量（bbb1.05 rj），在一些轨道上观察到强烈增强的局部磁场，并建立了在中高纬度地区识别强烈半球不对称的模型。这些特征可以通过识别与磁场相互作用引起的电离层密度变化来更好地解决，但过去的观测无法在空间上解决这些特征，-。在这项研究中，我们在木星赤道附近发现了一个弱H3+发射的暗正弦带，我们认为这是木星磁赤道的电离层特征。我们还观察到木星中纬度电离层的复杂结构，包括一个与朱诺号最近观测到的木星径向磁场局部增强相一致的黑点。这些特征揭示了木星电离层和磁场之间复杂的局部相互作用的证据。我们的结果为朱诺号航天器的观测和未来的电离层和磁场模型提供了基础事实。
Our understanding of Jupiter’s magnetic field has been developed through a combination of spacecraft measurements at distances >1.8RJand images of the aurora, , , , , –. These models all agree on the strength and direction of the Jovian dipole magnetic moments, but because higher-order magnetic moments decay more strongly with distance from the planet, past spacecraft measurements could not easily resolve them. In the past 2 years, the Juno mission has measured very close to the planet (>1.05RJ), observing a strongly enhanced localized magnetic field in some orbits,, and resulting in models that identify strong hemispheric asymmetries at mid-to-high latitudes,. These features could be better resolved by identifying changes in the ionospheric density caused by interactions with the magnetic field, but past observations have been unable to spatially resolve such features, –. In this study, we identify a dark sinusoidal ribbon of weakened H3+emission near the jovigraphic equator, which we show to be an ionospheric signature of Jupiter’s magnetic equator. We also observe complex structures in Jupiter’s mid-latitude ionosphere, including one dark spot that is coincident with a localized enhancement in Jupiter’s radial magnetic field observed recently by Juno. These features reveal evidence of complex localized interactions between Jupiter’s ionosphere and its magnetic field. Our results provide ground-truth for Juno spacecraft observations and future ionospheric and magnetic field models.