MAVEN and the total electron content of the Martian ionosphere. Issue 3 (7th March 2017)

• Record Type: Journal Article
• Authors: Mendillo, Michael; Narvaez, Clara; Vogt, Marissa F.; Mayyasi, Majd; Mahaffy, Paul; Benna, Mehdi; Andersson, Laila; Campbell, Bruce; Němec, Frantisek; Ma, Ying Juan; Chaufray, Jean‐Yves; Leblanc, François; Gonzalez‐Galindo, Francisco; Lopez‐Valverde, Miguel Ángel; Forget, François; Jakosky, Bruce
• Is Part Of: Journal of geophysical research. Volume 122:Issue 3(2017)
• Page Start: 3526
• Page End: 3537
• Publication Date: 2017-03-07
• Subjects: total electron content -- Mars -- MAVEN -- ionosphere; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/2016JA023474
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: Model studies of the ionosphere of Mars under daytime conditions reveal that for solar zenith angles of 0°–40°, the shapes and magnitudes of the electron density profiles Ne ( h ) change by only small amounts. This suggests that midday 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 Ne ( 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 Neutral Gas and Ion Mass Spectrometer and electron density by Langmuir Probe and Waves from periapse (~130 km) to 400 km were used to form 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 Ne ( 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 × 10 24 ions/s, an escape rate consistent with prior observation by Phobos‐2, Mars Express, and MAVEN's own in situ studies. Key Points: MAVEN's in situ plasma observations used to obtain topside ionosphere's total electron content validated by models and independent data MAVEN's April 2015 Deep‐Dip‐#2 campaign provided clear evidence of a topside depletion event A single ionopause contraction episode matched ambient plasma loss rates of ~3 × 10 24 ions/s