Abstract The Martian magnetotail current sheet serves as a critical pathway for ionospheric ion escape. Contrary to the conventional view that external magnetic pressure is balanced mainly by internal ion thermal pressure, we present novel observations from the Mars Atmosphere and Volatile Evolution spacecraft of an electron‐dominated pressure balance configuration. The current sheet electrons exhibit two distinct populations: a thermal core of ionospheric origin and a suprathermal shell of magnetosheath origin. Their bulk temperature reaches up to three times higher than that outside the current sheet. Based on linear instability analysis, we propose two candidate heating mechanisms: (a) Landau resonant or transit‐time heating by magnetosonic waves likely originating from the magnetosheath, and (b) Landau or cyclotron resonant heating by whistler and electron cyclotron harmonic waves generated spontaneously from the shell‐like electron velocity distribution. These results highlight the potentially significant role of plasma waves in sustaining the Martian atmospheric escape channels.
Observations from the Little Bunker
Last updated: November 30, 2025 04:25 AM
Atmospheric CO₂
426.8 ppm
+18.1
ppm/year
Atmospheric CH₄
1927.61 ppb
+2.73
ppb/year
Global Temperature
+1.48 °C
Peak: +1.73°C
World Population
8.1 billion
+67
million/year