DOI: 10.1002/2017JA024587
Scopus记录号: 2-s2.0-85046424396
论文题名: Formation of 30 KeV Proton Isotropic Boundaries During Geomagnetic Storms
作者: Dubyagin S. ; Ganushkina N.Y. ; Sergeev V.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 5 起始页码: 3436
结束页码: 3459
语种: 英语
英文关键词: EMIC waves
; geomagnetic storms
; isotropic boundaries
; magnetospheric models
; pitch angle scattering
英文摘要: We study the origin of the 30 keV proton isotropic boundary (IB) in the nightside auroral zone during geomagnetic storms, particularly, to address the recent results that the adiabaticity parameter K (ratio of the magnetic field line curvature radius to the particle gyroradius at the equator) on the IB field line can be much larger comparing to its theoretical estimate K ∼ 8 for the field line curvature (FLC) scattering mechanism. During nine storms in 2011–2013, we investigate ∼2,000 IBs observed by low-altitude Polar Operational Environmental Satellites (POES) satellites and apply the TS05 magnetospheric model to estimate the K value in the equatorial part of the IB field line. The statistical distribution of the estimated K parameter, while being rather broad, is centered on K = 9–13. For smaller subset of ∼250 IBs, the concurrent magnetic field measurements on board Time History of Events and Macroscale Interaction During Substorms probes in the equatorial magnetotail were used to correct the estimated K-values accounting for the TS05 deviations from the real magnetic configuration. After correction, the K distribution becomes narrower, being still centered on K = 9–12. Different estimates give percentages of events with K < 13, which can be attributed to IBs formed by FLC scattering, between 60% and 80%. Finally, we have not found any dependence of the K distribution on magnetic local time and IB latitude, except for events with IB located at extremely low latitudes (<59°). These findings imply that the FLC scattering is a dominant mechanism of IB formation operating in a variety of magnetospheric conditions. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113942
Appears in Collections: 气候减缓与适应
There are no files associated with this item.
作者单位: Finnish Meteorological Institute, Helsinki, Finland; Climate and Space Sciences and Engineering Department, University of Michigan, Ann Arbor, MI, United States; Department of Earth's Physics, St. Petersburg State University, St. Petersburg, Russian Federation
Recommended Citation:
Dubyagin S.,Ganushkina N.Y.,Sergeev V.. Formation of 30 KeV Proton Isotropic Boundaries During Geomagnetic Storms[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(5)