Search Publications
Effects of ion composition on escape and morphology on Mars
Zhang, Qi; Holmström, Mats; Wang, Xiao-Dong
We refine a recently presented method to estimate ion escape from non-magnetized planets and apply it to Mars. The method combines in situ observations and a hybrid plasma model (ions as particles, electrons as a fluid). We use measurements from the Mars Atmosphere and Volatile Evolution (MAVEN) mission and Mars Express (MEX) for one orbit on 1 Ma…
Estimating ion escape from unmagnetized planets
Holmstrom, Mats
We propose a new method to estimate ion escape from unmagnetized planets that combines observations and models. Assuming that upstream solar wind conditions are known, a computer model of the interaction between the solar wind and the planet is executed for different ionospheric ion production rates. This results in different amounts of mass loadi…
IMF-induced escape of molecular ions from the Martian ionosphere
Fujimoto, M.; Kubota, Y.; Maezawa, K. +1 more
Since Mars does not possess a significant global intrinsic magnetic field, the solar wind interacts directly with the Martian ionosphere and can induce ion escapes from it. Phobos-2 and recent Mars Express (MEX) observations have shown that the escaping ions are O+ as well as molecular O2+ and CO2+<…
Comparison of accelerated ion populations observed upstream of the bow shocks at Venus and Mars
Coates, A. J.; Fedorov, A.; Barabash, S. +12 more
Foreshock ions are compared between Venus and Mars at energies of 0.6~20 keV using the same ion instrument, the Ion Mass Analyser, on board both Venus Express and Mars Express. Venus Express often observes accelerated protons (2~6 times the solar wind energy) that travel away from the Venus bow shock when the spacecraft location is magnetically co…
Plasma boundary variability at Mars as observed by Mars Global Surveyor and Mars Express
Barabash, S.; Fränz, M.; Lester, M. +4 more
We have used Mars Express (MEX) and Mars Global Surveyor (MGS) simultaneous and non-simultaneous measurements to study the Martian plasma environment. In particular, we have derived quantitative expressions for the altitude of the terminator bow shock (BS) and magnetic pileup boundary (MPB) as functions of solar wind dynamic pressure, crustal magn…
Rosetta and Mars Express observations of the influence of high solar wind pressure on the Martian plasma environment
Barabash, S.; Lundin, R.; Fränz, M. +18 more
We report on new simultaneous in-situ observations at Mars from Rosetta and Mars Express (MEX) on how the Martian plasma environment is affected by high pressure solar wind. A significant sharp increase in solar wind density, magnetic field strength and turbulence followed by a gradual increase in solar wind velocity is observed during ~24 h in th…
Rosetta swing-by at Mars - an analysis of the ROMAP measurements in comparison with results of 3-D multi-ion hybrid simulations and MEX/ASPERA-3 data
Lundin, R.; Fränz, M.; Edberg, N. J. T. +8 more
The Rosetta spacecraft flew by Mars at a distance of 260 km on 25 February 2007 during a gravity assist manoeuvre. During the closest approach (CA) the lander magnetometer ROMAP was switched on. The dataset taken during this swingby provides insight into the plasma environment around Mars: in addition to a pronounced bow shock crossing Rosetta rec…
Access of solar wind electrons into the Martian magnetosphere
Barabash, S.; Lundin, R.; Winningham, J. D. +7 more
Electrons with energy of ~40 80 eV measured by the instrument ASPERA-3 on Mars Express and MAG-ER onboard Mars Global Surveyor are used to trace an access of solar wind electrons into the Martian magnetosphere. Crustal magnetic fields create an additional protection from solar wind plasma on the dayside of the Southern Hemisphere by shifting the b…
Comparison of plasma data from ASPERA-3/Mars-Express with a 3-D hybrid simulation
Barabash, S.; Lundin, R.; Krupp, N. +8 more
The ELS and IMA sensors of the ASPERA-3 experiment onboard of Mars-Express (MEX) can measure electron as well as ion moments. We compare these measurements for a specific orbit with the simulation results from a 3-D hybrid model. In the hybrid approximation the electrons are modeled as a massless charge-neutralizing fluid, whereas the ions are tre…