Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Modulation of Venus ion densities associated with solar variations

Journal Article · · Geophys. Res. Lett.; (United States)
;
The dayside ion concentrations in the Venus ionosphere obtained by the Pioneer Venus orbiter ion mass spectrometer exhibit a modulation corresponding to the 27-day solar variation. Comparisons were made of the amplitudes of modulation of CO/sub 2//sup +/, C/sup +/, and O/sub 2//sup +/, with the amplitudes of the 27-day variation in the 10.7 cm solar radio flux and the simultaneously measured EUV fluxes at He II (304 A) and Lyman ..beta.. (1026 A), together with a theoretical analysis of the effects of solar variability on the ionosphere and neutral atmosphere of Venus. This analysis leads us to the conclusion that the observed modulation of dayside ion densities is primarily due to the variability in the ionizing EUV radiations and, to a much lesser extent, the result of the variability with solar activity of the neutral atmosphere via the variability in exospheric temperature. In this connection, we also show, theoretically, why the percentage variation of exospheric temperature on Venus (as observed in the ONMS data) for a given variation in F/sub 10.7/, is only half of the exospheric temperature variation for Earth.
Research Organization:
NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771
OSTI ID:
5425649
Journal Information:
Geophys. Res. Lett.; (United States), Journal Name: Geophys. Res. Lett.; (United States) Vol. 8:7; ISSN GPRLA
Country of Publication:
United States
Language:
English

Similar Records

Response of Venus exospheric temperature measured by neutral mass spectrometer to solar EUV flux measured by Langmuir probe on the Pioneer Venus orbiter
Journal Article · Wed Jan 31 23:00:00 EST 1990 · Journal of Geophysical Research; (United States) · OSTI ID:5029352
Modulation of dayside on and neutral distributions at Venus. Evidence of direct and indirect solar energy inputs
Conference · Thu Dec 31 23:00:00 EST 1981 · Adv. Space Res.; (United States) · OSTI ID:6532558
Solar EUV measurements at Venus based on photoelectron emission from the Pioneer Venus Langmuir Probe
Journal Article · Fri Jul 01 00:00:00 EDT 1988 · Journal of Geophysical Research; (United States) · OSTI ID:5182655

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMBIENT TEMPERATURE
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON IONS
CARBON OXIDES
CHALCOGENIDES
CHARGED PARTICLES
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
EXOSPHERE
EXTREME ULTRAVIOLET RADIATION
ION DENSITY
IONS
OXIDES
OXYGEN COMPOUNDS
OXYGEN IONS
PIONEER SPACE PROBES
PLANETARY IONOSPHERES
PLANETS
RADIATIONS
SOLAR ACTIVITY
SPACE VEHICLES
ULTRAVIOLET RADIATION
VEHICLES
VENUS PLANET