Stream Interactions and Interplanetary Coronal Mass Ejections at 5.3 AU near the Solar Ecliptic Plane
Stream Interactions and Interplanetary Coronal Mass Ejections at 5.3 AU near the Solar Ecliptic Plane
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DOI：
10.1007/s11207-008-9204-x
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发表时间：
2008-06
期刊：
影响因子：
2.8
通讯作者：
L. Jian;C. Russell;J. Luhmann;R. Skoug;J. Steinberg
中科院分区：
文献类型：
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作者：
L. Jian;C. Russell;J. Luhmann;R. Skoug;J. Steinberg
我们利用尤利西斯号的太阳风观测结果，对接近 5.3 个天文单位的两种大型空间尺度太阳风结构、流相互作用区域 (SIR) 和行星际日冕物质抛射 (ICME) 的特征进行了调查。我们的研究范围仅限于《尤利西斯》的三个远日点经过，并且也在太阳黄道面± 10°范围内，覆盖了1992年、1997年—1998年和2003年—2005年的部分时间，代表了太阳活动周期不同阶段的三个切片。总体而言，调查中有 54 个 SIR 和 60 个 ICME。许多在混合事件中合并，表明它们在到达木星轨道之前经历了多次相互作用。大约 91% 的 SIR 伴随着冲击而发生，其中 47% 的冲击是正向-反向冲击对。太阳风速度有时在 5.3 AU 附近的相互作用区域内保持恒定甚至减小，与 1 AU 的 SIR 期间速度逐渐增加相反。 58% 的 ICME 引发冲击，其中 94% 是前向冲击。一些 ICME 似乎有多个不同规模和特性的小磁通绳。我们定量比较了 5.3 个天文单位的 SIR 和 ICME 的各种特性，并研究了它们的统计分布和随太阳活动的变化。 SIR 的宽度、最大动压力和峰值垂直压力都变得比 ICME 更大。动态压力（Pdyn）预计对木星磁层活动很重要。我们已经研究了 SIR、ICME 和一般太阳风的 Pdyn 分布，但这些无法解释观测到的木星磁层顶位置的双峰分布。通过比较 SIR 和 ICME 在 0.72、1 和 5.3 AU 时的特性，我们发现 ICME 扩张在 1 和 5.3 AU 之间显着减慢。日光层内部的一些短暂的小流已经合并成一个相互作用区域。
We have performed a survey of the characteristics of two types of large spatial-scale solar-wind structures, stream interaction regions (SIRs), and interplanetary coronal mass ejections (ICMEs), near 5.3 AU, using solar-wind observations fromUlysses. Our study is confined to the three aphelion passes ofUlysses, and also within ± 10° of the solar ecliptic plane, covering a part of 1992, 1997 – 1998, and 2003 – 2005, representing three slices of different phases of the solar activity cycle. Overall, there are 54 SIRs and 60 ICMEs in the survey. Many are merged in hybrid events, suggesting that they have undergone multiple interactions prior to reaching Jovian orbit. About 91% of SIRs occur with shocks, with 47% of such shocks being forward – reverse shock pairs. The solar-wind velocity sometimes stays constant or even decreases within the interaction region near 5.3 AU, in contrast with the gradual velocity increase during SIRs at 1 AU. Shocks are driven by 58% of ICMEs, with 94% of them being forward shocks. Some ICMEs seem to have multiple small flux ropes with different scales and properties. We quantitatively compare various properties of SIRs and ICMEs at 5.3 AU, and study their statistical distributions and variations with solar activity. The width, maximum dynamic pressure, and peak perpendicular pressure of SIRs all become larger than ICMEs. Dynamic pressure (Pdyn) is expected to be important for Jovian magnetospheric activity. We have examined the distributions ofPdynof SIRs, ICMEs, and general solar wind, but these cannot explain the observed bimodal distribution of the location of the Jovian magnetopause. By comparing the properties of SIRs and ICMEs at 0.72, 1, and 5.3 AU, we find that the ICME expansion slows down significantly between 1 and 5.3 AU. Some transient and small streams in the inner heliosphere have merged into a single interaction region.