Charged particle periodicity in the Saturnian magnetosphere
Charged particle periodicity in the Saturnian magnetosphere
复制标题
土星磁层中的带电粒子周期性
DOI：
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发表时间：
1982
期刊：
影响因子：
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通讯作者：
S. Krimigis
中科院分区：
文献类型：
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作者：
J. Carbary;S. Krimigis
旅行者1号和2号航天器上的低能带电粒子（LECP）实验在1980年和1981年的土星遭遇期间对电子（122 keV至120 MeV）和离子（128 keV至150 MeV）进行了测量。两个低能量电子（22至35千电子伏和183至500千电子伏）和离子（43至80千电子伏和137至215千电子伏）通道的计数率比表现出约10小时的周期外土星磁层超出土卫六的轨道。电子比从1050到10300不等;离子比从1030到1020不等。类似的，但不太明显的周期性观察较高和较低的能量电子和离子的光谱指数。在旅行者2号的外太空部分观测到三个完整的周期，其中电子比周期为10小时21米± 48米，离子比周期为9小时49米± 59米。使用土星公里辐射（SKR）和土星静电放电（SED）周期，从旅行者2号到旅行者1号的向后外推表明，周期性本质上是土星的，而不是木星的，并且它们的相位持续时间至少长达287天。比率极小值或光谱硬化，与极光增亮、SKR活动和轮辐增强发生在同一半球。我们解释的意见，初步证据表明，在土星磁场的不对称性和观察到的SKR周期性的根本原因。
The Low Energy Charged Particle (LECP) experiments on the Voyager 1 and 2 spacecraft performed measurements of electrons (∼22 keV to ∼20 MeV) and ions (∼28 keV to ∼150 MeV) during the Saturn encounters in 1980 and 1981. Count rate ratios of two of the low energy electron (22 to 35 keV and 183 to 500 keV) and ion (43 to 80 keV and 137 to 215 keV) channels exhibit an approximate 10 hour periodicity in the outer Saturnian magnetosphere beyond the orbit of Titan. Electron ratios vary from ∼50 to ∼300; ion ratios vary from ∼3 to ∼20. Similar but less pronounced periodicities are observed for higher and lower energy electron and ion spectral indices. Three complete cycles were observed during the Voyager 2 outbound portion of the encounter from which were determined an electron ratio period of 10h21m±48m and an ion ratio period of 9h49m±59m. Using Saturn Kilometric Radiation (SKR) and Saturn Electrostatic Discharge (SED) periods, extrapolation backward from Voyager 2 to Voyager 1 suggests that the periodicities are Saturnian rather than Jovian in nature, and that they persist in phase for time intervals at least as long as 287 days. Ratio minima, or spectral hardenings, occur in the same hemisphere as do auroral brightenings, SKR activity, and spoke enhancement. We interpret the observations as prima facie evidence of an asymmetry in the Saturnian magnetic field and the root cause of the observed SKR periodicity.