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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, …
Energization of Plasma Species by Intermittent Kinetic Alfvén Waves
Goossens, Marcel; Voitenko, Yuriy
We propose a new phase-mixing sweep model of coronal heating and solar wind acceleration based on dissipative properties of kinetic Alfvén waves (KAWs). The energy reservoir is provided by the intermittent ∼1 Hz MHD Alfvén waves excited at the coronal base by magnetic restructuring. These waves propagate upward along open magnetic field lines, pha…
ICMEs in the Outer Heliosphere and at High Latitudes: An Introduction
Richardson, J. D.; von Steiger, R.
Interplanetary coronal mass ejections (ICMEs) are observed at all latitudes and distances from which data are available. We discuss the radial evolution of ICMEs out to large distances and ICME properties at high latitudes. The internal pressure of ICMEs initially exceeds the ambient solar wind pressure and causes the ICMEs to expand in radial wid…
Solar Energetic Particle Charge States: An Overview
Klecker, B.; Möbius, E.; Popecki, M. A.
The ionic charge distributions of solar energetic particles (SEP) as observed in interplanetary space provide fundamental information about the origin of these particles, and the acceleration and propagation processes at the Sun and in interplanetary space. In this paper we review the measurements of ionic charge states of energetic particles in i…
Wind in the Solar Corona: Dynamics and Composition
Antonucci, Ester
The dynamics of the solar corona as observed during solar minimum with the Ultraviolet Coronagraph Spectrometer, UVCS, on SOHO is discussed. The large quiescent coronal streamers existing during this phase of the solar cycle are very likely composed by sub-streamers, formed by closed loops and separated by open field lines that are channelling a s…
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…
Location of Magnetic Reconnection in the Magnetotail
Nagai, Tsugunobu
It is a crucial issue to know where magnetic reconnection takes place in the near-Earth magnetotail for substorm onsets. It is found on the basis of Geotail observations that the factor that controls the magnetic reconnection site in the magnetotail is the solar wind energy input. Magnetic reconnection forms close to (far from) the Earth in the ma…
Microphysics of Magnetic Reconnection
Retinò, Alessandro; Vaivads, Andris; André, Mats
Magnetic reconnection is a universal phenomenon where energy is efficiently converted from the magnetic field to charged particles as a result of global magnetic topology changes during which earlier separated plasma regions become magnetically connected. While the reconnection affects large volumes in space most of the topology changes and of the…
Interaction of the Solar Wind with Weak Obstacles: Hybrid Simulations for Weakly Active Comets and for Mars
Kührt, E.; Motschmann, U.
Obstacles in the solar wind are weak when their extension is small or comparable to the characteristic ion gyroradii. In this case interactions involve kinetic features, and hybrid models are an adequate description. A hybrid code operating on a curvilinear 3D grid and its application to solar wind interaction with weak obstacles is discussed. The…