The extension of ionospheric holes into the tail of Venus. Issue 8 (28th August 2014)

• Record Type: Journal Article
• Authors: Collinson, G. A.; Fedorov, A.; Futaana, Y.; Masunaga, K.; Hartle, R.; Stenberg, G.; Grebowsky, J.; Holmström, M.; Andre, N.; Barabash, S.; Zhang, T. L.
• Is Part Of: Journal of geophysical research. Volume 119:Issue 8(2014:Aug.)
• Page Start: 6940
• Page End: 6953
• Publication Date: 2014-08-28
• Subjects: Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/2014JA019851
• Languages: English
• ISSNs: 2169-9380

Abstract

<abstract abstract-type="main" id="jgra51213-abs-0001"> <title>Abstract</title> <p>Ionospheric holes are Cytherian nightside phenomena discovered by the NASA <italic>Pioneer Venus Orbiter</italic>, featuring localized plasma depletions driven by prominent and unexplained enhancements in the draped interplanetary magnetic field. Observed only during solar maximum, the phenomenon remains unexplained, despite their frequent observation during the first 3 years of the mission and more than 30 years having elapsed since their first description in the literature. We present new observations by the European Space Agency <italic>Venus Express</italic> showing that ionospheric holes can extend much further into the tail than previously anticipated (1.2 to 2.4 planetary radii) and may be observed throughout the solar cycle and over a wide range of solar wind conditions. We find that ionospheric holes are a manifestation of a deeper underlying phenomenon: tubes of enhanced draped interplanetary magnetic field that emerge in pairs from below the ionosphere and stretch far down the tail. We speculate on two possible explanations for the magnetic fields underlying the phenomena: magnetic pileup due to stagnation of ionospheric flow and internal draping around a metallic core.</p> </abstract>