Correlations between enhanced electron temperatures and electric field wave power in the Martian ionosphere

C. M. Fowler , L. Andersson , W. K. Peterson , J. Halekas , A. F. Nagy , R. E. Ergun , J. Espley , D. L. Mitchell , J. E. P. Connerney , C. Mazelle (1) , P. R. Mahaffy , B. M. Jakosky

1 IRAP - Institut de recherche en astrophysique et planétologie

Statistical correlations are reported between measured electron temperatures and total electric field wave power (in the 2-100 Hz frequency range), at Mars' subsolar point ionosphere. The observations, made by the Mars Atmosphere and Volatile EvolutioN spacecraft, suggest that electric field wave power from the Mars-solar wind interaction propagates through the Martian ionosphere and is able to heat ionospheric electrons by over 1000 K. Such heating can account for a substantial (but likely not complete) fraction of previously reported discrepancies between modeled and observed electron temperatures in Mars' upper ionosphere. Wave power is typically less than observable thresholds below altitudes of about 200 km, suggesting that energy is deposited into the ionosphere above this. Observed total wave powers range between 10^-12 and 10^-9 (V/m)² and decrease with increasing integrated electron density (or decreasing altitude).

Mots clés: electron; heating; Mars; ionosphere

Domaines: Planète et Univers [physics]

C. M. Fowler, L. Andersson, W. K. Peterson, J. Halekas, A. F. Nagy, et al.. Correlations between enhanced electron temperatures and electric field wave power in the Martian ionosphere. Geophysical Research Letters, 2018, 45, pp.493-501. ⟨10.1002/2017GL073387⟩. ⟨insu-03678246⟩