The diffuse aurora: A significant source of ionization in the middle atmosphere
Citations Over TimeTop 10% of 1997 papers
Abstract
Energetic electrons can penetrate into the middle atmosphere causing excitation, dissociation, and ionization of neutral constituents, resulting in chemical changes. In this paper, representative electron spectra measured by the Upper Atmosphere Research Satellite particle environment monitor are used to determine the relative contributions of bremsstrahlung X rays and direct electron impact on the energy deposition and ionization production rates for altitudes between 20 and 150 km. Above 50 km most of the ionization comes from direct electron impact. However, in the stratosphere the energy contributed below 50 km is mostly due to bremsstrahlung X rays. In the diffuse aurora the ionization from the bremsstrahlung component exceeds that due to the galactic cosmic ray background to altitudes as low as 30 km during geomagnetically active periods. This paper demonstrates that a diffuse auroral source can input as much or more energy into the upper portion of the lower and middle atmosphere as previously reported for relativistic electron events. The effects of the diffuse aurora (including both the direct electron and the bremsstrahlung contributions) on atmospheric chemistry may be significant.
Related Papers
- → Stratospheric and tropospheric components of 7Be in surface air(1985)120 cited
- → Tritiated water vapor in the stratosphere: Vertical profiles and residence time(2002)35 cited
- → Intercomparison of measurements of stratospheric hydrogen fluoride(1990)23 cited
- → In situ measurements of NOx in the Airborne Arctic Stratospheric Expedition(1990)28 cited
- → Cosmogenic and bomb-produced7Be in stratospheric air(1980)