土星磁层中等离子体的组成与动力学

Composition and dynamics of plasma in Saturn's magnetosphere.

作者信息

Young D T, Berthelier J-J, Blanc M, Burch J L, Bolton S, Coates A J, Crary F J, Goldstein R, Grande M, Hill T W, Johnson R E, Baragiola R A, Kelha V, McComas D J, Mursula K, Sittler E C, Svenes K R, Szegö K, Tanskanen P, Thomsen M F, Bakshi S, Barraclough B L, Bebesi Z, Delapp D, Dunlop M W, Gosling J T, Furman J D, Gilbert L K, Glenn D, Holmlund C, Illiano J-M, Lewis G R, Linder D R, Maurice S, McAndrews H J, Narheim B T, Pallier E, Reisenfeld D, Rymer A M, Smith H T, Tokar R L, Vilppola J, Zinsmeyer C

机构信息

Southwest Research Institute, San Antonio, TX 78238, USA.

出版信息

Science. 2005 Feb 25;307(5713):1262-6. doi: 10.1126/science.1106151.

DOI:10.1126/science.1106151

PMID:15731443

Abstract

During Cassini's initial orbit, we observed a dynamic magnetosphere composed primarily of a complex mixture of water-derived atomic and molecular ions. We have identified four distinct regions characterized by differences in both bulk plasma properties and ion composition. Protons are the dominant species outside about 9 RS (where RS is the radial distance from the center of Saturn), whereas inside, the plasma consists primarily of a corotating comet-like mix of water-derived ions with approximately 3% N+. Over the A and B rings, we found an ionosphere in which O2+ and O+ are dominant, which suggests the possible existence of a layer of O2 gas similar to the atmospheres of Europa and Ganymede.

摘要

在卡西尼号的初始轨道运行期间，我们观测到一个动态磁层，其主要由源自水的原子离子和分子离子的复杂混合物构成。我们已识别出四个不同区域，这些区域的特征在于整体等离子体特性和离子组成均存在差异。在约9个土星半径（RS，即从土星中心起的径向距离）之外，质子是主要成分，而在其内部，等离子体主要由与水相关的离子组成的共转彗星状混合物构成，其中约含3%的N⁺。在A环和B环上方，我们发现了一个以O₂⁺和O⁺为主的电离层，这表明可能存在一层类似于木卫二和木卫三大气层的O₂气体。