MAVEN and the total electron content of the Martian ionosphere

Michael Mendillo (1) , Clara Narvaez (1) , Marissa F. Vogt (1) , Majd Mayyasi (1) , Paul Mahaffy (2) , Mehdi Benna (2) , Laila Anderson (3) , Bruce Campbell (4) , Frantisek Němec (5) , Ying Juan Ma (6) , Jean-Yves Chaufray (7) , François Leblanc (7) , Francisco Gonzalez-Galindo (8) , Miguel Ángel Lopez-Valverde (8) , François Forget (9) , Bruce Jakosky (3)

1 CSP - Center for Space Physics [Boston]
2 GSFC - NASA Goddard Space Flight Center
3 LASP - Laboratory for Atmospheric and Space Physics [Boulder]
4 Smithsonian Institution
5 Faculty of Mathematics and Physics [Praha/Prague]
6 UCLA - University of California [Los Angeles]
7 HELIOS - LATMOS
8 IAA - Instituto de Astrofísica de Andalucía
9 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)

Model studies of the ionosphere of Mars under daytime conditions reveal that for solar zenith angles (SZAs) of 0°-40°, the shapes and magnitudes of the electron density profiles N_e(h) change by only small amounts. This suggests that mid-day observations made by MAVEN instruments along slanted orbit segments can be used to represent vertical profiles. The total electron content (TEC), defined as the height integral of N_e(h), is a measure of the cold plasma reservoir of the martian ionosphere. During MAVEN's Deep-Dip-#2 campaign of April 2015, observations of total ion density by NGIMS and electron density by LPW from periapse (~130 km) to 400 km were used to form < TEC > topside—validated by independent diagnostics and models. Orbit-by-orbit changes in topside TEC were then used to assess the magnitudes of plasma escape associated with both large and small changes in the topside slope of N_e(h)—called an “ionopause episode.” The TEC changes due to these episodes, generalized to a global change, resulted in an escape flux of ~3 - 6 x 10²⁴ ions/sec, an escape rate consistent with prior observation by Phobos-2, Mars Express, and MAVEN's own in-situ studies.

Keywords: MAVEN; Ionosphere; Total electron content; Mars

Domains: Space Physics [physics.space-ph]

Michael Mendillo, Clara Narvaez, Marissa F. Vogt, Majd Mayyasi, Paul Mahaffy, et al.. MAVEN and the total electron content of the Martian ionosphere. Journal of Geophysical Research Space Physics, 2017, 122 (3), pp.3526-3537. ⟨10.1002/2016JA023474⟩. ⟨insu-01471028⟩