Survey of 1-Hz waves in the near-Venusian space: Venus Express observations. (August 2020)

• Record Type: Journal Article
• Authors: Xiao, S.D.; Wu, M.Y.; Wang, G.Q.; Chen, Y.Q.; Zhang, T.L.
• Is Part Of: Planetary and space science. Volume 187(2020)
• Publication Date: 2020-08
• Subjects: Space sciences -- Periodicals; Atmosphere, Upper -- Periodicals; Sciences spatiales -- Périodiques; Haute atmosphère -- Périodiques; 523
• DOI: 10.1016/j.pss.2020.104933
• Languages: English
• ISSNs: 0032-0633

Abstract

Abstract: With 32 ​Hz magnetic field data of Venus Express from May 2006 to August 2012, the global spatial distributions of 1-Hz waves in the near-Venusian space are presented in this paper. The occurrence rate of 1-Hz waves is maximized near the Venusian bow shock and decreases in the upstream with the distance away from the shock. Downstream of Venusian bow shock, some 1-Hz waves are swept in the magnetosheath. However, these waves cannot enter the induced magnetosphere. The distribution of 1-Hz waves shows a solar cycle variation which could be the influence of the newborn pickup ions. The wave occurrence rate is higher near the bow shock in the -E hemisphere, and the waves can propagate upstream farther in the +E hemisphere, while the occurrence rate of the downstream 1-Hz waves shows no clear hemispheric asymmetry. In addition, the 1-Hz waves in the near-Venusian space have a higher occurrence rate and a more widespread distribution in the quasi-parallel foreshock region than in the quasi-perpendicular region. It can be inferred that the 1-Hz waves in the quasi-parallel region are less affected by Landau damping and they can propagate farther in the foreshock. Highlights: The global spatial distributions of 1-Hz waves near Venus are presented. The distribution of 1-Hz waves is related to the solar activity. The upstream 1-Hz waves show a ​± ​E hemispheric asymmetry. The distribution of the wave occurrence rate is dependent on the shock normal angle.