Magnetospheric period oscillations at Saturn: Comparison of equatorial and high-latitude magnetic field periods with north and south Saturn kilometric radiation periods
Magnetospheric period oscillations at Saturn: Comparison of equatorial and high-latitude magnetic field periods with north and south Saturn kilometric radiation periods
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土星磁层周期振荡：赤道和高纬度磁场周期与南北土星千米辐射周期的比较
DOI：
10.1029/2010ja015666
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Andrews D
中科院分区：
文献类型：
--
作者：
Andrews D
最近使用卡西尼号无线电数据表明，在2004年至2009年年中近春分期间的南方夏季条件下，土星南北半球的土星公里辐射受到明显不同的周期调制，北部的∼为10.6h，南部的∼为10.8h。在这里，我们研究了卡西尼号磁层磁场在同一时间间隔内的数据，并表明两个相应的磁场振荡系统也存在，它们的总周期与相应的SKR调制相同，到∼为0.01%。具体地，我们证明了南方开场线上的旋转准偶极场扰动和闭合场线内区的旋转准均匀场与南方SKR调制具有相同的周期，但存在一些起源未知的缓慢的长期相移，而北方开场线上的旋转准偶极场扰动与北方SKR调制具有相同的周期。我们还发现，当赤道准均匀场和有效的南横偶极子在南SKR极大值处沿着尾部朝向黎明方向时，对应的北侧横向偶极子方向大致相反，在北SKR极大值处指向太阳，也略微朝向黎明。我们根据两个独立的高纬度场向电流系统的存在来讨论这些发现，这些电流系统在两个半球以不同的周期旋转。
It has recently been shown using Cassini radio data that Saturn kilometric radiation (SKR) emissions from the Northern and Southern hemispheres of Saturn are modulated at distinctly different periods, ∼10.6 h in the north and ∼10.8 h in the south, during the southern summer conditions that prevailed during the interval from 2004 to near‐equinox in mid‐2009. Here we examine Cassini magnetospheric magnetic field data over the same interval and show that two corresponding systems of magnetic field oscillations that have the same overall periods, as the corresponding SKR modulations, to within ∼0.01% are also present. Specifically, we show that the rotating quasi‐dipolar field perturbations on southern open field lines and the rotating quasi‐uniform field in the inner region of closed field lines have the same period as the southern SKR modulations, although with some intervals of slow long‐term phase drift of unknown origin, while the rotating quasi‐dipolar field perturbations on northern open field lines have the same period as the northern SKR modulations. We also show that while the equatorial quasi‐uniform field and effective southern transverse dipole are directed down tail and toward dawn at southern SKR maxima, as found in previous studies, the corresponding northern transverse dipole is directed approximately opposite, pointing sunward and also slightly toward dawn at northern SKR maxima. We discuss these findings in terms of the presence of two independent high‐latitude field‐aligned current systems that rotate with different periods in the two hemispheres.
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土星磁层极光电流系统的特征：高纬度卡西尼号观测
DOI：
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发表时间：
2009
期刊：
影响因子：
--
作者：
C. Arridge;A. Coates;D. Talboys;E. Bunce;S. Cowley;M. Dougherty
通讯作者：
M. Dougherty
太阳风速对土星无线电钟的调制
影响因子：
64.8
作者：
P. Zarka;L. Lamy;B. Cecconi;R. Prangé;H. Rucker
通讯作者：
H. Rucker
DOI：
--
发表时间：
2000
期刊：
影响因子：
--
作者：
S. A. Espinosa;M. Dougherty
通讯作者：
M. Dougherty
DOI：
--
发表时间：
2008
期刊：
影响因子：
--
作者：
W. Kurth;T. Averkamp;D. Gurnett;J. Groene;A. Lecacheux
通讯作者：
A. Lecacheux
DOI：
--
发表时间：
1982
期刊：
影响因子：
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作者：
J. Carbary;S. Krimigis
通讯作者：
S. Krimigis