Search Publications
The Rosetta Ion and Electron Sensor (IES) measurement of the development of pickup ions from comet 67P/Churyumov-Gerasimenko
Goldstein, R.; Mokashi, P.; Clark, G. +9 more
The Rosetta Ion and Electron Sensor (IES) has been measuring solar wind ions intermittently since exiting from hibernation in May 2014. On 19 August, when Rosetta was ~80 km from the comet 67P/Churyumov-Gerasimenko, which was ~3.5 AU from the Sun, IES began to see ions at its lowest energy range, ~4-10 eV. We identify these as ions created from ne…
Slow electron phase space holes: Magnetotail observations
André, M.; Vaivads, A.; Khotyaintsev, Y. V. +1 more
We report multispacecraft observations of slow electrostatic solitary waves in the plasma sheet boundary layer. The electrostatic solitary waves are embedded in a region with field-aligned electron flows and are interpreted as electron phase space holes. We make unambiguous velocity and length estimates of the electron holes, vEH∼500 km…
Evolution of the plasma environment of comet 67P from spacecraft potential measurements by the Rosetta Langmuir probe instrument
André, M.; Carr, C.; Edberg, N. J. T. +6 more
We study the evolution of the plasma environment of comet 67P using measurements of the spacecraft potential from early September 2014 (heliocentric distance 3.5 AU) to late March 2015 (2.1 AU) obtained by the Langmuir probe instrument. The low collision rate keeps the electron temperature high (∼5 eV), resulting in a negative spacecraft potential…
Titan's interaction with the supersonic solar wind
Dougherty, M. K.; Kurth, W. S.; Hospodarsky, G. +5 more
9 years in the Saturn system, the Cassini spacecraft finally observed Titan in the supersonic and super-Alfvénic solar wind. These unique observations reveal that Titan's interaction with the solar wind is in many ways similar to unmagnetized planets Mars and Venus and active comets in spite of the differences in the properties of the solar plasma…
Venus's major cloud feature as an equatorially trapped wave distorted by the wind
Sánchez-Lavega, A.; López-Valverde, M. A.; Machado, P. +2 more
The superrotation of the atmospheres of slowly rotating bodies is a long-standing problem yet unsolved in atmospheric dynamics. On Venus, the most extreme case known of superrotation, this is accompanied and influenced by a recurrent planetary-scale cloud structure, known as the Y feature. So far, no model has simultaneously reproduced its shape, …
Charge exchange in cometary coma: Discovery of H- ions in the solar wind close to comet 67P/Churyumov-Gerasimenko
Goldstein, R.; Mokashi, P.; Tzou, C. -Y. +4 more
As Rosetta was orbiting comet 67P/Churyumov-Gerasimenko, the Ion and Electron Sensor detected negative particles with angular distributions like those of the concurrently measured solar wind protons but with fluxes of only about 10% of the proton fluxes and energies of about 90% of the proton energies. Using well-known cross sections and energy-lo…
Simultaneous field-aligned currents at Swarm and Cluster satellites
Dunlop, M. W.; Carr, C. M.; Bogdanova, Y. V. +13 more
We show for the first time, with direct, multispacecraft calculations of electric current density, and other methods, matched signatures of field-aligned currents (FACs) sampled simultaneously near the ionosphere at low (~500 km altitude) orbit and in the magnetosphere at medium (~2.5 RE altitude) orbits using a particular Swarm and Clu…
Slow electron holes in multicomponent plasmas
André, M.; Vaivads, A.; Khotyaintsev, Yu. V. +2 more
Electrostatic solitary waves (ESWs), often interpreted as electron phase space holes, are commonly observed in plasmas and are manifestations of strongly nonlinear processes. Often slow ESWs are observed, suggesting generation by the Buneman instability. The instability criteria, however, are generally not satisfied. We show how slow electron hole…
Observation of charged nanograins at comet 67P/Churyumov-Gerasimenko
Goldstein, R.; Mokashi, P.; Gombosi, T. I. +2 more
Soon after the Rosetta Orbiter rendezvoused with comet 67P/Churyumov-Gerasimenko at a solar distance of ~3.5 AU and began to fly in triangular-shaped trajectories around it, the Ion and Electron Sensor detected negative particles at energies from about 100 eV/q to over 18 keV/q. The lower energy particles came from roughly the direction of the com…
Birkeland current effects on high-latitude ground magnetic field perturbations
Anderson, B. J.; Snekvik, K.; Østgaard, N. +8 more
Magnetic perturbations on ground at high latitudes are directly associated only with the divergence-free component of the height-integrated horizontal ionospheric current, J⊥,df. Here we show how J⊥,df can be expressed as the total horizontal current J⊥ minus its curl-free component, the latter being completely det…