The impact of an ICME on the Jovian X-ray aurora.
The impact of an ICME on the Jovian X-ray aurora.
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DOI：
10.1002/2015ja021888
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发表时间：
2016-03
期刊：
影响因子：
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通讯作者：
Jasinski JM
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文献类型：
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作者：
Dunn WR;Branduardi-Raymont G;Elsner RF;Vogt MF;Lamy L;Ford PG;Coates AJ;Gladstone GR;Jackman CM;Nichols JD;Rae IJ;Varsani A;Kimura T;Hansen KC;Jasinski JM
我们报告了计划与行星际日冕物质抛射（ICME）相一致的第一次木星X射线观测。在预测的ICME到达时间，我们观察到木星X射线极光的增强因子为108。在这种增强的1.5小时内，发生了强烈的非木卫一十米波射电爆发。空间、光谱和时间特征在ICME到达和两天后的另一次X射线观测之间也有所不同。Gladstone等人（2002）发现了极区X射线热点，并发现它以45分钟的准周期脉冲。在ICME到达期间，热点扩大并表现出两个周期：硫离子的26分钟周期和碳/硫和氧离子的混合物的12分钟周期。ICME后，优势期变为42 min。通过比较沃格特等人（2011）的木星映射模型和光谱分析，我们发现在ICME到达期间，至少有两种不同的离子群，来自木星的昼面，产生了X射线极光。极光映射到50和70 R J之间的磁层场线，主要是来自沉淀硫离子（S7+，...，14+）的发射。排放映射到封闭的场线之间的70和120 R J和开放的场线产生的沉淀氧（O 7+，8+）和硫/碳离子的混合物，可能意味着一些太阳风降水。我们认为X射线热点的最佳解释是脉冲昼侧重联扰动磁层向下电流，如Bunce等人（2004）所提出的。极光增强具有与热点不同的光谱、空间和时间特征。通过分析这些特征和一致的无线电发射，我们提出增强是由ICME通过木星磁层压缩和/或大规模的昼侧重联事件直接驱动的。ICME的到来改变了木星的X射线极光光谱、空间和时间特征木星的X射线极光映射到外磁层的源，也映射到开放场线木星的X射线极光是由ICME期间两种不同的离子群产生的。
We report the first Jupiter X‐ray observations planned to coincide with an interplanetary coronal mass ejection (ICME). At the predicted ICME arrival time, we observed a factor of ∼8 enhancement in Jupiter's X‐ray aurora. Within 1.5 h of this enhancement, intense bursts of non‐Io decametric radio emission occurred. Spatial, spectral, and temporal characteristics also varied between ICME arrival and another X‐ray observation two days later. Gladstone et al. (2002) discovered the polar X‐ray hot spot and found it pulsed with 45 min quasiperiodicity. During the ICME arrival, the hot spot expanded and exhibited two periods: 26 min periodicity from sulfur ions and 12 min periodicity from a mixture of carbon/sulfur and oxygen ions. After the ICME, the dominant period became 42 min. By comparing Vogt et al. (2011) Jovian mapping models with spectral analysis, we found that during ICME arrival at least two distinct ion populations, from Jupiter's dayside, produced the X‐ray aurora. Auroras mapping to magnetospheric field lines between 50 and 70 R J were dominated by emission from precipitating sulfur ions (S7+,…,14+). Emissions mapping to closed field lines between 70 and 120 R J and to open field lines were generated by a mixture of precipitating oxygen (O7+,8+) and sulfur/carbon ions, possibly implying some solar wind precipitation. We suggest that the best explanation for the X‐ray hot spot is pulsed dayside reconnection perturbing magnetospheric downward currents, as proposed by Bunce et al. (2004). The auroral enhancement has different spectral, spatial, and temporal characteristics to the hot spot. By analyzing these characteristics and coincident radio emissions, we propose that the enhancement is driven directly by the ICME through Jovian magnetosphere compression and/or a large‐scale dayside reconnection event. The arrival of an ICME changes Jupiter's X‐ray auroral spectra, spatial, and temporal characteristics Jupiter's X‐ray aurora maps to sources in the outer magnetosphere and also to open field lines Jupiter's X‐ray aurora is produced by two distinct ion populations during the ICME