A note on the ring current in Saturn's magnetosphere: Comparison of magnetic data obtained during the Pioneer-11 and Voyager-1 and -2 fly-bys
A note on the ring current in Saturn's magnetosphere: Comparison of magnetic data obtained during the Pioneer-11 and Voyager-1 and -2 fly-bys
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关于土星磁层环流的注释：Pioneer-11 与 Voyager-1 和-2 飞越期间获得的磁数据的比较
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
S. Cowley
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作者：
E. Bunce;S. Cowley
摘要。我们研究了先锋11号在1979年飞掠土星时观测到的残余（测量减去内部）磁场矢量，并将其与旅行者1号和2号在1980年和1981年飞掠土星时观测到的磁场矢量进行了比较。我们首次表明，在先驱者11号遭遇期间，磁层内存在环电流系统，其性质与旅行者号飞越时的环电流系统相似。然而，分析还显示，在先驱者11号与土星相遇时，环电流比旅行者1号飞越火星时更靠近土星，这反映了当时磁层更压缩的本质。剩余场矢量使用Connerney等人（1981a）提出的木星当前系统的自适应进行拟合。一个与先锋-11号土星数据相当吻合的模型径向延伸在6.5到12.5 RS之间（与非扇区磁层顶距离为17 RS相比），南北延伸范围为4 RS，总电流为9.6 MA。Connerney et al.（1983）先前确定的与旅行者号数据在质量上相似的相应模型，径向延伸在8至15.5 RS之间（与旅行者1号的非扇形磁层顶距离为23-24 RS相比），南北延伸范围为6 RS，总电流为11.5 MA。关键字。磁层物理（电流系统，磁层结构和动力学，行星磁层）
Abstract. We examine the residual (measured minus internal) magnetic field vectors observed in Saturn’s magnetosphere during the Pioneer-11 fly-by in 1979, and compare them with those observed during the Voyager-1 and -2 fly-bys in 1980 and 1981. We show for the first time that a ring current system was present within the magnetosphere during the Pioneer-11 encounter, which was qualitatively similar to those present during the Voyager fly-bys. The analysis also shows, however, that the ring current was located closer to the planet during the Pioneer-11 encounter than during the comparable Voyager-1 fly-by, reflecting the more com-pressed nature of the magnetosphere at the time. The residual field vectors have been fit using an adaptation of the current system proposed for Jupiter by Connerney et al. (1981a). A model that provides a reasonably good fit to the Pioneer-11 Saturn data extends radially between 6.5 and 12.5 RS (compared with a noon-sector magnetopause distance of 17 RS ), has a north-south extent of 4 RS , and carries a total current of 9.6 MA. A corresponding model that provides a qualitatively similar fit to the Voyager data, determined previously by Connerney et al. (1983), extends radially between 8 and 15.5 RS (compared with a noon-sector magnetopause distance for Voyager-1 of 23–24 RS ), has a north-south extent of 6 RS , and carries a total current of 11.5 MA. Key words. Magnetospheric physics (current systems, magnetospheric configuration and dynamics, planetary magnetospheres)