DOI: 10.1002/2017JA024913
Scopus记录号: 2-s2.0-85041183967
论文题名: Ionospheric Irregularities at Mars Probed by MARSIS Topside Sounding
作者: Harada Y. ; Gurnett D.A. ; Kopf A.J. ; Halekas J.S. ; Ruhunusiri S.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 1 起始页码: 1018
结束页码: 1030
语种: 英语
英文关键词: ionosphere
; ionospheric irregularities
; Mars
; MARSIS
英文摘要: The upper ionosphere of Mars contains a variety of perturbations driven by solar wind forcing from above and upward propagating atmospheric waves from below. Here we explore the global distribution and variability of ionospheric irregularities around the exobase at Mars by analyzing topside sounding data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express. As irregular structure gives rise to off-vertical echoes with excess propagation time, the diffuseness of ionospheric echo traces can be used as a diagnostic tool for perturbed reflection surfaces. The observed properties of diffuse echoes above unmagnetized regions suggest that ionospheric irregularities with horizontal wavelengths of tens to hundreds of kilometers are particularly enhanced in the winter hemisphere and at high solar zenith angles. Given the known inverse dependence of neutral gravity wave amplitudes on the background atmospheric temperature, the ionospheric irregularities probed by MARSIS are most likely associated with plasma perturbations driven by atmospheric gravity waves. Though extreme events with unusually diffuse echoes are more frequently observed for high solar wind dynamic pressures during some time intervals, the vast majority of the diffuse echo events are unaffected by varying solar wind conditions, implying limited influence of solar wind forcing on the generation of ionospheric irregularities. Combination of remote and in situ measurements of ionospheric irregularities would offer the opportunity for a better understanding of the ionospheric dynamics at Mars. ©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/114857
Appears in Collections: 气候减缓与适应
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作者单位: Department of Physics and Astronomy, University of Iowa, Iowa City, IA, United States
Recommended Citation:
Harada Y.,Gurnett D.A.,Kopf A.J.,et al. Ionospheric Irregularities at Mars Probed by MARSIS Topside Sounding[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(1)