Long-term variability of [SII] emissions from the Io plasma torus between 1997 and 2000
Long-term variability of [SII] emissions from the Io plasma torus between 1997 and 2000
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DOI：
10.1029/2003ja010241
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发表时间：
2004-07-21
影响因子：
2.8
通讯作者：
Sood, R
中科院分区：
文献类型：
--
作者：
Nozawa, H;Misawa, H;Sood, R
对木卫一等离子体环面的长期光学观测提供了大量关于木星磁层等离子体环境的信息。我们利用可移动望远镜系统对木卫一等离子体环面[SII]辐射（lambdalambda673.1, 671.6 nm）进行了1997年至2000年的成像观测。从这些数据中，我们获得了强度变化和平均径向剖面，并发现等离子体环面在1997年至2000年间经历了系统的长期变化，这表明木卫一的火山活动多年来一直在减少。我们研究了环面辐射强度的周期性，证实了环面等离子体在10.2小时左右被调制，对应于所谓的系统IV周期，并且环面没有长期的系统III周期。
Long-term optical observation of the Io plasma torus provides a great deal of information on the plasma environment in the Jovian magnetosphere. We made imaging observations of [SII] emissions (lambdalambda673.1, 671.6 nm) from the Io plasma torus using a transportable telescope system for the period from 1997 to 2000. From the data we obtained intensity variations and average radial profiles and found that the plasma torus underwent systematic long-term variations between 1997 and 2000, indicating that Io's volcanic activity has been reducing over the years. We investigated the periodicity of torus emission intensity and confirmed that torus plasma is modulated at about 10.2 hours, corresponding to the so-called System IV period, and that the torus has no long-term System III periodicity.