EarthRef.org Reference Database (ERR)
Development and Maintenance by the EarthRef.org Database Team

Detailed Reference Information
Ho et al. 1993
Ho, C.M., Strangeway, R.J., Russell, C.T., Luhmann, J.G. and Brace, L.H. (1993). The nightside ionosphere of Venus under varying levels of solar Euv flux. Geophysical Research Letters 20: doi: 10.1029/93GL02484. issn: 0094-8276.

Solar activity varied widely over the 14 year lifetime of the Pioneer Venus Orbiter, and these variations directly affected the properties of the nightside ionosphere. At solar maximum, when solar EUV was largest, the Venus ionosphere was found to extend to highest altitudes and nightward ion transport was the main source of the nightside ionosphere. At solar minimum, nightward ion transport was reduced, and electron precipitation was thought to be the main source. In this study, we have attempted a separation of spatial variations from temporal variations by examining the altitude profiles of the magnetic field, and electron density and temperature for three different solar EUV flux ranges. In the upper ionosphere and near-planet magnetotail (h>1800 km), the solar EUV effects are significant. The electron density decreases about an order of magnitude from high to low EUV flux, while the electron temperature at least doubles. The magnetic field also increases 2--3 nT. In the lower ionosphere (200--600 km), lower EUV fluxes are associated with slightly reduced density, and higher temperature. These results are in accord with recent entry phase observations, where the electron density measured above the ionospheric density peak is lower than that observed at solar maximum during the early Pioneer Venus mission. ¿ American Geophysical Union 1993

BACKGROUND DATA FILES

Abstract

Keywords
Planetology, Solid Surface Planets and Satellites, Ionospheres, Ionosphere, Planetary ionospheres, Ionosphere, Solar radiation and cosmic ray effects
Journal
Geophysical Research Letters
http://www.agu.org/journals/gl/
Publisher
American Geophysical Union
2000 Florida Avenue N.W.
Washington, D.C. 20009-1277
USA
1-202-462-6900
1-202-328-0566
service@agu.org
Click to clear formClick to return to previous pageClick to submit