DOI: 10.1002/2017JA024434
Scopus记录号: 2-s2.0-85041121064
论文题名: Variations of High-Latitude Geomagnetic Pulsation Frequencies: A Comparison of Time-of-Flight Estimates and IMAGE Magnetometer Observations
作者: Sandhu J.K. ; Yeoman T.K. ; James M.K. ; Rae I.J. ; Fear R.C.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 1 起始页码: 567
结束页码: 586
语种: 英语
英文关键词: field line eigenfrequencies
; field line resonances
; IMAGE
; mass density
; time-of-flight
; ULF waves
英文摘要: The fundamental eigenfrequencies of standing Alfvén waves on closed geomagnetic field lines are estimated for the region spanning 5.9≤L < 9.5 over all MLT (Magnetic Local Time). The T96 magnetic field model and a realistic empirical plasma mass density model are employed using the time-of-flight approximation, refining previous calculations that assumed a relatively simplistic mass density model. An assessment of the implications of using different mass density models in the time-of-flight calculations is presented. The calculated frequencies exhibit dependences on field line footprint magnetic latitude and MLT, which are attributed to both magnetic field configuration and spatial variations in mass density. In order to assess the validity of the time-of-flight calculated frequencies, the estimates are compared to observations of FLR (Field Line Resonance) frequencies. Using IMAGE (International Monitor for Auroral Geomagnetic Effects) ground magnetometer observations obtained between 2001 and 2012, an automated FLR identification method is developed, based on the cross-phase technique. The average FLR frequency is determined, including variations with footprint latitude and MLT, and compared to the time-of-flight analysis. The results show agreement in the latitudinal and local time dependences. Furthermore, with the use of the realistic mass density model in the time-of-flight calculations, closer agreement with the observed FLR frequencies is obtained. The study is limited by the latitudinal coverage of the IMAGE magnetometer array, and future work will aim to extend the ground magnetometer data used to include additional magnetometer arrays. ©2018. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114785
Appears in Collections: 气候减缓与适应
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作者单位: Department of Space and Climate Physics, Mullard Space Science Laboratory, University College London, Dorking, United Kingdom; Department of Physics and Astronomy, University of Leicester, Leicester, United Kingdom; Department of Physics and Astronomy, University of Southampton, Southampton, United Kingdom
Recommended Citation:
Sandhu J.K.,Yeoman T.K.,James M.K.,et al. Variations of High-Latitude Geomagnetic Pulsation Frequencies: A Comparison of Time-of-Flight Estimates and IMAGE Magnetometer Observations[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(1)