Observations of Sounder Accelerated Electrons by Mars Express. Issue 1 (9th January 2020)

• Record Type: Journal Article
• Authors: Barabash, S.; Voshchepynets, A.; Holmstrom, M.; Frahm, R. A.; Nillsson, H.; Andrews, D.; Kopf, A.; Winningham, J. D.
• Is Part Of: Journal of geophysical research. Volume 125:Issue 1(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-01-09
• Subjects: Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2019JA027206
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: The electron sensor of the Analyzer of Space Plasmas and Energetic Atoms experiment detects accelerated electrons during pulses of radio emissions from the powerful topside sounder: the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) on board the Mars Express spacecraft. Accelerated electrons are observed at energies up to 400 eV at the times when MARSIS transmits at a frequency between the local plasma frequency and its harmonics (up to 4 times the plasma frequency). When the electron density and magnetic field strength are low ( ∼ 1 0 3 cm − 3, ∼ 10 nT), the accelerated electrons are almost monoenergetic electron beams. An increase in density and magnetic field ( ∼ 3 · 1 0 3 cm − 3, ∼ 50 nT) leads to substantial broadening of the energy spectrum of the accelerated electrons. It is concluded that in the latter case, electrons are accelerated by the variable spacecraft potential resulting from the imbalance of the electron and ion currents to the MARSIS antenna during transmission. Key Points: Accelerated electrons are detected by the electron sensor of ASPERA‐3 during the sounding phase of the Mars Express sounder MARSIS The energy of the accelerated electrons is found to be in the range from 20 to 400 eV Observations coincide in time with periods when MARSIS transmits in frequencies between the local plasma frequency and its fourth harmonic