DOI: 10.1029/2018JA025426
Scopus记录号: 2-s2.0-85052631783
论文题名: Saturn's Northern Auroras and Their Modulation by Rotating Current Systems During Late Northern Spring in Early 2014
作者: Kinrade J. ; Badman S.V. ; Provan G. ; Cowley S.W.H. ; Lamy L. ; Bader A.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 8 起始页码: 6289
结束页码: 6306
语种: 英语
英文摘要: The Hubble Space Telescope imaged Saturn's northern ultraviolet auroras during February–June 2014, when Saturn's northern and southern magnetic perturbation fields were locked in antiphase and matched in rotation period (~10.69 hr). During this coalescence period, we test for evidence of rotational modulation of the auroras using the latest rotating current system model and kilometric radio phases derived from Cassini measurements. While we see modulation of auroral intensity in the rotating frames of the planetary period current systems, the pattern is opposite to that expected and is dominated by an asymmetric local time profile that peaks at dawn. Enhancement of the north emission by rotating upward field aligned currents (FACs) is expected to peak at magnetic longitudes of ~90°, whereas here the intensity increased at ~270°. This unexpected finding is attributed to the presence of nonplanetary period oscillation dynamics having affected the auroral morphology, together with insufficient sampling of the rotational system orientations provided during such Hubble Space Telescope campaigns. Rotational modulation is clearest at dawn regardless of the pattern's orientation, suggesting that the physical relationship between rotating FACs and auroral intensity is not direct, having a local time dependence that is not generally observed in the rotating FAC magnitudes. We also find no statistically significant planetary period oscillation of the auroral circle position, but the mean center was offset from the spin pole by ~3° latitude toward early morning local times. Mean auroral boundaries were located at equatorward and poleward colatitudes of 15.0 ± 2.8° and 12.4 ± 3.0°, respectively. ©2018. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113290
Appears in Collections: 气候减缓与适应
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作者单位: Physics Department, Lancaster University, Lancaster, United Kingdom; Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom; LESIA, Observatoire de Paris, CNES, PSL, Meudon, France
Recommended Citation:
Kinrade J.,Badman S.V.,Provan G.,et al. Saturn's Northern Auroras and Their Modulation by Rotating Current Systems During Late Northern Spring in Early 2014[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(8)