IMF dependence of Saturn's auroras: modelling study of HST and Cassini data from 12–15 February 2008
IMF dependence of Saturn's auroras: modelling study of HST and Cassini data from 12–15 February 2008
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土星极光的 IMF 依赖性：2008 年 2 月 12 日至 15 日 HST 和卡西尼号数据的建模研究
DOI：
10.5194/angeo-28-1559-2010
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发表时间：
2010
影响因子：
1.9
通讯作者：
G. Provan
中科院分区：
文献类型：
--
作者：
E. Belenkaya;I. Alexeev;M. Blokhina;E. Bunce;S. Cowley;J. Nichols;V. Kalegaev;V. Petrov;G. Provan
抽象的。为了更好地了解土星磁层中的极光过程，我们将哈勃太空望远镜（HST）获得的紫外线（UV）极光图像与电离层中开闭磁力线边界的位置进行比较，该位置是使用磁场模型计算的，该磁场模型采用卡西尼号测量的行星际磁场（IMF）作为输入。继 2004 年 1 月卡西尼号位于距土星约 1300 土星半径的早期相关研究之后，我们在这里研究了 2008 年 2 月 12 日至 15 日期间的数据，当时 HST 获得了土星南部日面极光的紫外图像，同时卡西尼号航天器测量了日面弓激波上游太阳风中的 IMF。因此，这种配置提供了迄今为止独一无二的机会，可以确定在成像观测期间撞击土星磁层的 IMF，而无需考虑长期且不确定的行星际传播延迟。然后采用土星磁层的抛物面模型来计算平均 IMF 向量的磁层磁场结构和电离层开闭场线边界，这些向量在适当的响应延迟下对应于四个 HST 图像。我们表明，根据模型计算出的依赖于 IMF 的开放场区域与紫外线发射的极地区域相当吻合，从而支持了日侧电离层中土星极光椭圆形的极地边界位于开闭场线边界附近的观点。
Abstract. To gain better understanding of auroral processes in Saturn's magnetosphere, we compare ultraviolet (UV) auroral images obtained by the Hubble Space Telescope (HST) with the position of the open-closed field line boundary in the ionosphere calculated using a magnetic field model that employs Cassini measurements of the interplanetary magnetic field (IMF) as input. Following earlier related studies of pre-orbit insertion data from January 2004 when Cassini was located ~ 1300 Saturn radii away from the planet, here we investigate the interval 12–15 February 2008, when UV images of Saturn's southern dayside aurora were obtained by the HST while the Cassini spacecraft measured the IMF in the solar wind just upstream of the dayside bow shock. This configuration thus provides an opportunity, unique to date, to determine the IMF impinging on Saturn's magnetosphere during imaging observations, without the need to take account of extended and uncertain interplanetary propagation delays. The paraboloid model of Saturn's magnetosphere is then employed to calculate the magnetospheric magnetic field structure and ionospheric open-closed field line boundary for averaged IMF vectors that correspond, with appropriate response delays, to four HST images. We show that the IMF-dependent open field region calculated from the model agrees reasonably well with the area lying poleward of the UV emissions, thus supporting the view that the poleward boundary of Saturn's auroral oval in the dayside ionosphere lies adjacent to the open-closed field line boundary.
DOI：
10.1029/2008ja013257
发表时间：
2008-09
期刊：
Scopus
影响因子：
--
作者：
E. Bunce;C. Arridge;J. Clarke;A. Coates;S. Cowley;M. Dougherty;Jean-Claude Gérard;D. Grodent;K. Hansen;J. Nichols;D. Southwood;D. Southwood;D. Talboys
通讯作者：
E. Bunce;C. Arridge;J. Clarke;A. Coates;S. Cowley;M. Dougherty;Jean-Claude Gérard;D. Grodent;K. Hansen;J. Nichols;D. Southwood;D. Southwood;D. Talboys
太阳风共转相互作用区域与土星千米辐射爆发的相位和强度之间的关系
影响因子：
1.9
作者：
Badman S
通讯作者：
Badman S