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Ionospheric control of the dawn‐dusk asymmetry of the Mars magnetotail current sheet
Author(s) -
Liemohn Michael W.,
Xu Shaosui,
Dong Chuanfei,
Bougher Stephen W.,
Johnson Blake C.,
Ilie Raluca,
De Zeeuw Darren L.
Publication year - 2017
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja023707
Subject(s) - physics , interplanetary magnetic field , geophysics , ionosphere , current sheet , plasma sheet , mars exploration program , magnetosheath , magnetosphere , solar wind , magnetopause , magnetic field , astronomy , magnetohydrodynamics , quantum mechanics
This study investigates the role of solar EUV intensity at controlling the location of the Mars magnetotail current sheet and the structure of the lobes. Four simulation results are examined from a multifluid magnetohydrodynamic model. The solar wind and interplanetary magnetic field (IMF) conditions are held constant, and the Mars crustal field sources are omitted from the simulation configuration. This isolates the influence of solar EUV. It is found that solar maximum conditions, regardless of season, result in a Venus‐like tail configuration with the current sheet shifted to the − Y (dawnside) direction. Solar minimum conditions result in a flipped tail configuration with the current sheet shifted to the + Y (duskside) direction. The lobes follow this pattern, with the current sheet shifting away from the larger lobe with the higher magnetic field magnitude. The physical process responsible for this solar EUV control of the magnetotail is the magnetization of the dayside ionosphere. During solar maximum, the ionosphere is relatively strong and the draped IMF field lines quickly slip past Mars. At solar minimum, the weaker ionosphere allows the draped IMF to move closer to the planet. These lower altitudes of the closest approach of the field line to Mars greatly hinder the day‐to‐night flow of magnetic flux. This results in a buildup of magnetic flux in the dawnside lobe as the S‐shaped topology on that side of the magnetosheath extends farther downtail. The study demonstrates that the Mars dayside ionosphere exerts significant control over the nightside induced magnetosphere of that planet.