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Radial Evolution of Coronal Mass Ejections Between MESSENGER, Venus Express, STEREO, and L1: Catalog and Analysis
Lugaz, N.; Winslow, R. M.; Salman, T. M.
Our knowledge of the properties of coronal mass ejections (CMEs) in the inner heliosphere is constrained by the relative lack of plasma observations between the Sun and 1 AU. In this work, we present a comprehensive catalog of 47 CMEs measured in situ measurements by two or more radially aligned spacecraft (MESSENGER, Venus Express, STEREO, Wind/A…
Foreshock Bubbles at Venus: Hybrid Simulations and VEX Observations
Omidi, N.; Collinson, G.; Sibeck, D.
In the absence of a global magnetic field at Venus, its ionosphere is the obstacle to the flow of the solar wind resulting in the formation of a smaller bow shock and foreshock. Spacecraft observations and global hybrid (kinetic ions, fluid electrons) simulations have demonstrated that despite its smaller size, the foreshock at Venus has propertie…
Foreshock Cavities at Venus and Mars
Zhang, Tielong; Futaana, Yoshifumi; Frahm, Rudy +7 more
"Foreshock cavities" are regions of turbulent and heated solar wind plasma that form upstream of Earth's bow shock. Despite being common at Earth, none have yet been reported at other planets. Here we present a survey of events encountered by the ESA Venus Express spacecraft consistent with foreshock cavities at Venus and a case study of a foresho…
Turbulence Near the Venusian Bow Shock: Venus Express Observations
Zhang, T. L.; Vörös, Z.; Chen, Y. Q. +3 more
In terms of composition and size, Venus is an Earth-like planet without a global intrinsic magnetic field. The Venusian bow shock and magnetosheath, reaching only 10% of the size of the Earth, are formed from the interaction of the solar wind with the Venusian ionosphere. Energy injection from the solar wind to the Venusian space environment can b…
Dependence of Dayside Electron Densities at Venus on Solar Irradiance
Pätzold, M.; Häusler, B.; Tellmann, S. +3 more
The ionosphere of Venus is a weakly ionized plasma layer embedded in the planet's upper atmosphere. Planetary ionospheres provide an excellent opportunity to study how our variable Sun affects the planets in our solar system. Because ionospheres are reservoirs from which atmospheric species can be lost to space, studying how ionospheres respond to…
Dependence of the Interplanetary Magnetic Field on Heliocentric Distance at 0.3-1.7 AU: A Six-Spacecraft Study
Hanneson, Cedar; Johnson, Catherine L.; Mittelholz, Anna +2 more
We use magnetometer data taken simultaneously by MESSENGER, VEX, STEREO and ACE to characterize the variation of the interplanetary magnetic field (IMF) with heliocentric distance, rh, for rh≲ 1 AU. Power law fits (a rh b) to the individual IMF components and magnitude indicate that, on average, the IMF is more tightly wound and its strength decre…
A Survey of Venus Shock Crossings Dominated by Kinematic Relaxation
Pope, S. A.
Collisionless shocks are one of the most effective particle accelerators in the known universe. Even low Mach number shocks could have a significant role in particle heating and acceleration. Theory suggests that kinematic collisionless relaxation, the process whereby a downstream nongyroptopic ion population becomes thermalized through collisionl…