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Ionospheric photoelectrons: Comparing Venus, Earth, Mars and Titan
Coates, A. J.; Barabash, S.; Lundin, R. +6 more
The sunlit portion of planetary ionospheres is sustained by photoionization. This was first confirmed using measurements and modelling at Earth, but recently the Mars Express, Venus Express and Cassini-Huygens missions have revealed the importance of this process at Mars, Venus and Titan, respectively. The primary neutral atmospheric constituents …
Dynamics and circulation regimes of terrestrial planets
Read, P. L.
By the study of simple analogues, either in the form of simplified numerical models or laboratory experiments, considerable insights may be gained as to the likely roles of planetary size, rotation, thermal stratification and other factors in determining the principal length scales, styles of global circulation and dominant waves and instability p…
Comparative study of ion cyclotron waves at Mars, Venus and Earth
Russell, C. T.; Wei, H. Y.; Zhang, T. L. +1 more
Ion cyclotron waves are generated in the solar wind when it picks up freshly ionized planetary exospheric ions. These waves grow from the free energy of the highly anisotropic distribution of fresh pickup ions, and are observed in the spacecraft frame with left-handed polarization and a wave frequency near the ion's gyrofrequency. At Mars and Venu…
Sulfuric acid aerosols in the atmospheres of the terrestrial planets
Grinspoon, David H.; Toon, Owen B.; McGouldrick, Kevin
Clouds and hazes composed of sulfuric acid are observed to exist or postulated to have once existed on each of the terrestrial planets with atmospheres in our solar system. Venus today maintains a global cover of clouds composed of a sulfuric acid/water solution that extends in altitude from roughly 50 km to roughly 80 km. Terrestrial polar strato…
Magnetic states of the ionosphere of Venus observed by Venus Express
Barabash, S.; Woch, J.; Fränz, M. +4 more
Strong ultraviolet radiation from the Sun ionizes the upper atmosphere of Venus, creating a dense ionosphere on the dayside of the planet. In contrast to Earth, the ionosphere of Venus is not protected against the solar wind by a magnetic field. However, the interaction between charged ionospheric particles and the solar wind dynamic and magnetic …
Modeling the atmospheric limb emission of CO 2 at 4.3 µm in the terrestrial planets
López-Puertas, M.; López-Valverde, M. A.; Gilli, G. +5 more
The MIPAS instrument on board Envisat, in Earth orbit, the PFS and OMEGA instruments on Mars Express, and VIRTIS on board Venus Express are currently providing a dataset of limb measurements of the CO 2 atmospheric fluorescence emission at 4.3-µm from the upper atmosphere of the three planets. These measurements represent an excel…
Atmospheric chemistry on Venus, Earth, and Mars: Main features and comparison
Krasnopolsky, Vladimir A.
This paper deals with two common problems and then considers major aspects of chemistry in the atmospheres of Mars and Venus. (1) The atmospheres of the terrestrial planets have similar origins but different evolutionary pathways because of the different masses and distances to the Sun. Venus lost its water by hydrodynamic escape, Earth lost CO
Modelling the atmospheric CO 2 10-µm non-thermal emission in Mars and Venus at high spectral resolution
Sornig, M.; Sonnabend, G.; Kroetz, P. +1 more
A study of the CO 2 atmospheric emissions at 10-µm in the upper atmospheres of Mars and Venus is performed in order to explain a number of ground-based measurements of these emissions recently taken at very high spectral resolution in both planets. The measurements are normally used to derive atmospheric temperatures and winds, bu…
Venus lightning: Comparison with terrestrial lightning
Russell, C. T.; Wei, H. Y.; Zhang, T. L. +2 more
Terrestrial lightning is generated by the separation of electric charge residing on water-ice particles in clouds, a few kilometers above the electrically conducting surface of the Earth. It is detected optically, electromagnetically, and aurally. The majority of discharges occur within or between clouds with about one third discharging to the sur…
Studying methane and other trace species in the Mars atmosphere using a SOIR instrument
Daerden, F.; Robert, S.; Neary, L. +7 more
Solar Occultation in the InfraRed (SOIR) is one of three spectrometers of the SPICAV/SOIR instrument suite ( Bertaux et al., 2007b) on board the Venus Express orbiter (VEX). VEX has been in orbit around Venus since April 2006 and to date SOIR has carried out over 674 measurements. Pre-launch and in-orbit performance analyses allow us to predict wh…