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The Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) for the Mars Express Mission
Coates, A. J.; Kallio, E.; Fedorov, A. +39 more
The general scientific objective of the ASPERA-3 experiment is to study the solar wind - atmosphere interaction and to characterize the plasma and neutral gas environment with within the space near Mars through the use of energetic neutral atom (ENA) imaging and measuring local ion and electron plasma. The ASPERA-3 instrument comprises four sensor…
Plasma Morphology at Mars. Aspera-3 Observations
Barabash, S.; Lundin, R.; Winningham, J. D. +6 more
A total of about of 400 orbits during the first year of the ASPERA-3 operation onboard the Mars Express spacecraft were analyzed to obtain a statistical pattern of the main plasma domains in the Martian space environment. The environment is controlled by the direct interaction between the solar wind and the planetary exosphere/ionosphere which res…
Locations of Atmospheric Photoelectron Energy Peaks Within the Mars Environment
Coates, A. J.; Kallio, E.; Barabash, S. +13 more
By identifying peaks in the photoelectron spectrum produced by photoionization of CO2 in the Martian atmosphere, we have conducted a pilot study to determine the locations of these photoelectrons in the space around Mars. The significant result of this study is that these photoelectrons populate a region around Mars bounded externally b…
Plasma Moments in the Environment of Mars. Mars Express ASPERA-3 Observations
Coates, A. J.; Fedorov, A.; Barabash, S. +7 more
We present the first electron and ion moment maps (density, velocity and temperature) of the martian plasma environment, using data from the ELS and IMA sensors of the ASPERA-3 experiment onboard Mars Express. Moments are calculated by integration and by Gaussian fits to the phase space distribution. The methods of calculation and the calibration …
Observations of Vertical Reflections from the Topside Martian Ionosphere
Gurnett, D. A.; Morgan, D. D.; Orosei, R. +7 more
The Martian ionosphere has for the first time been probed by a low frequency topside radio wave sounder experiment (MARSIS) (Gurnett et al., 2005). The density profiles in the Martian ionosphere have for the first time been observed for solar zenith angles less than 48 degrees. The sounder spectrograms typically have a single trace of echoes, whic…
The Hydrogen Exospheric Density Profile Measured with ASPERA-3/NPD
Barabash, S.; Lundin, R.; Holmström, M. +6 more
We have evaluated the Lyman-α limb emission from the exospheric hydrogen of Mars measured by the neutral particle detector of the ASPERA-3 instrument on Mars Express in 2004 at low solar activity (solar activity index = 42, F10.7=100). We derive estimates for the hydrogen exobase density, nH = 1010 m−3, …
Mars Global MHD Predictions of Magnetic Connectivity Between the Dayside Ionosphere and the Magnetospheric Flanks
Liemohn, Michael W.; Barabash, Stas; Lundin, Rickard +7 more
Atmospheric photoelectrons have been observed well above the ionosphere of Mars by the ASPERA-3 ELS instrument on Mars Express. To systematically interpret these observations, field lines from two global MHD simulations were analyzed for connectivity to the dayside ionosphere (allowing photoelectron escape). It is found that there is a hollow cyli…
Auroral Plasma Acceleration Above Martian Magnetic Anomalies
Coates, A. J.; Kallio, E.; Fedorov, A. +25 more
Aurora is caused by the precipitation of energetic particles into a planetary atmosphere, the light intensity being roughly proportional to the precipitating particle energy flux. From auroral research in the terrestrial magnetosphere it is known that bright auroral displays, discrete aurora, result from an enhanced energy deposition caused by dow…
Energetic Hydrogen and Oxygen Atoms Observed on the Nightside of Mars
Fedorov, A.; Barabash, S.; Lundin, R. +5 more
We present measurements of energetic hydrogen and oxygen atoms (ENAs) on the nightside of Mars detected by the neutral particle detector (NPD) of ASPERA-3 on Mars Express. We focus on the observations for which the field-of-view of NPD was directed at the nightside of Mars or at the region around the limb, thus monitoring the flow of ENAs towards …
IMF Direction Derived from Cycloid-Like Ion Distributions Observed by Mars Express
Coates, A. J.; Kallio, E.; Fedorov, A. +29 more
Although the Mars Express (MEX) does not carry a magnetometer, it is in principle possible to derive the interplanetary magnetic field (IMF) orientation from the three dimensional velocity distribution of pick-up ions measured by the Ion Mass Analyser (IMA) on board MEX because pick-up ions' orbits, in velocity phase space, are expected to gyrate …