DOI: 10.1029/2017JA024920
Scopus记录号: 2-s2.0-85050890891
论文题名: Magnetically Controlled Density Structures in the Martian Ionosphere: Are they Stably Recurring?
作者: Mohanamanasa P. ; Venkateswara Rao N. ; Yaswanth C. ; Rao S.V.B.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 7 起始页码: 5790
结束页码: 5806
语种: 英语
英文关键词: density structures
; magnetic fields
; Mars ionosphere
; MARSIS
; nightside Martian ionosphere
; repeatability
英文摘要: MARSIS instrument aboard the Mars Express spacecraft regularly detects the magnetically controlled density structures (MCDSs) in the Martian ionosphere. In this paper, we studied the recurrence characteristics of these MCDSs using long-term (more than a decade) MARSIS observations over a selected region of 35° to 40° longitude and −10° to 10° latitude, where a strong magnetic anomaly is present. Instead of a conventional echogram analysis, we used the peak density echogram analysis as the latter is able to consider all the vertical and oblique echoes even if their peak densities are varying. The results of the present study show that MCDSs are in fact formed persistently on all dayside periapsis passes. More importantly, there are discontinuities in the hyperbola shape in a peak density echogram display that appear at different locations on different orbital passes. In addition, the apices of the hyperbolas associated with an MCDS are observed at different latitudes on different orbital passes. From these results, we infer that the locations and shapes of MCDSs are disturbed by some time-varying external factors so that some parts of the MCDS cannot give specular reflections. These hypotheses were demonstrated with some simple ray propagation simulations. Nearly similar features are observed with the nightside MCDS, but they occur only 60% of the passes. We surmise that wave dynamics associated with tides and gravity waves and so forth might be responsible for altering the shape and location of MCDS, both on the dayside and nightside. ©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/113666
Appears in Collections: 气候减缓与适应
There are no files associated with this item.
作者单位: Department of Physics, S. V. University, Tirupati, India; National Atmospheric Research Laboratory, Gadanki, India
Recommended Citation:
Mohanamanasa P.,Venkateswara Rao N.,Yaswanth C.,et al. Magnetically Controlled Density Structures in the Martian Ionosphere: Are they Stably Recurring?[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(7)