土卫六与土星磁层相互作用产生的高能中性原子发射。

Energetic neutral atom emissions from Titan interaction with Saturn's magnetosphere.

作者信息

Mitchell D G, Brandt P C, Roelof E C, Dandouras J, Krimigis S M, Mauk B H

机构信息

Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 21042, USA.

出版信息

Science. 2005 May 13;308(5724):989-92. doi: 10.1126/science.1109805.

DOI:10.1126/science.1109805

PMID:15890874

Abstract

The Cassini Magnetospheric Imaging Instrument (MIMI) observed the interaction of Saturn's largest moon, Titan, with Saturn's magnetosphere during two close flybys of Titan on 26 October and 13 December 2004. The MIMI Ion and Neutral Camera (INCA) continuously imaged the energetic neutral atoms (ENAs) generated by charge exchange reactions between the energetic, singly ionized trapped magnetospheric ions and the outer atmosphere, or exosphere, of Titan. The images reveal a halo of variable ENA emission about Titan's nearly collisionless outer atmosphere that fades at larger distances as the exospheric density decays exponentially. The altitude of the emissions varies, and they are not symmetrical about the moon, reflecting the complexity of the interactions between Titan's upper atmosphere and Saturn's space environment.

摘要

卡西尼号磁层成像仪器（MIMI）在2004年10月26日和12月13日对土卫六进行的两次近距离飞掠期间，观测了土星最大的卫星土卫六与土星磁层的相互作用。MIMI离子与中性粒子相机（INCA）持续对由高能单电离捕获磁层离子与土卫六外层大气（即外逸层）之间的电荷交换反应产生的高能中性原子（ENA）进行成像。图像显示出土卫六几乎无碰撞的外层大气周围有一个可变的ENA发射晕，随着外逸层密度呈指数衰减，该晕在更大距离处逐渐消失。发射的高度各不相同，且关于卫星不对称，这反映出土卫六上层大气与土星空间环境之间相互作用的复杂性。