Long‐lived auroral structures and atmospheric losses through auroral flux tubes on Mars

Abstract

The ASPERA‐3 observations of electron and ion fluxes over the regions dominated by crustal magnetic fields show the existence of long‐lived and active aurora‐type magnetic flux tubes with a width of 20–150 km. The activity manifests itself by large electron energy fluxes (≥10−4 W/m2) and strong distortions in the upper (350–400 km) ionosphere. In some events the peaked electron energy distributions typical for Earth aurora are so pronounced that they are present in velocity distribution functions. A significant depletion of such auroral flux tubes is accompanied by the appearance of oxygen beams and a heating of the ions of ionospheric origin. Auroral activity was observed on several subsequent orbits of the Mars Express spacecraft during more than two weeks implying a stable existence of aurora on Mars. Atmospheric loss driven by energy deposition in the auroral flux tubes is estimated as ∼1023 s−1.