caa a22 4500 445815868 CHVBK 20180317145228.0 cr unu---uuuuu 170323e20111201xx s 000 0 eng 10.1007/s11214-011-9811-y doi (NATIONALLICENCE)springer-10.1007/s11214-011-9811-y Lundin Rickard Swedish Institute of Space Physics, Teknikhuset, 90187, Umea, Sweden aut Ion Acceleration and Outflow from Mars and Venus: An Overview [Elektronische Daten] [Rickard Lundin] Solar wind forcing of Mars and Venus results in outflow and escape of ionospheric ions. Observations show that the replenishment of ionospheric ions starts in the dayside at low altitudes (≈300-800km), ions moving at a low velocity (5-10km/s) in the direction of the external/ magnetosheath flow. At high altitudes, in the inner magnetosheath and in the central tail, ions may be accelerated up to keV energies. However, the dominating energization and outflow process, applicable for the inner magnetosphere of Mars and Venus, leads to outflow at energies ≈5-20eV. The aim of this overview is to analyze ion acceleration processes associated with the outflow and escape of ionospheric ions from Mars and Venus. Qualitatively, ion acceleration may be divided in two categories: (a) Modest ion acceleration, leading to bulk outflow and/or return flow (circulation). (b) Acceleration to well over escape velocity, up into the keV range. In the first category we find a processes denoted "planetary wind”, the result of e.g. ambipolar diffusion, wave enhanced planetary wind, and mass-loaded ion pickup. In the second category we find ion pickup, current sheet acceleration, wave acceleration, and parallel electric fields, the latter above Martian crustal magnetic field regions. Both categories involve mass loading. Highly mass-loaded ion energization may lead to a low-velocity bulk flow—A consequence of energy and momentum conservation. It is therefore not self-evident what group, or what processes are connected with the low-energy outflow of ionospheric ions from Mars. Experimental and theoretical findings on ionospheric ion acceleration and outflow from Mars and Venus are discussed in this report. Springer Science+Business Media B.V., 2011 Mars and Venus nationallicence Ionospheric ion acceleration nationallicence Plasma escape nationallicence Space Science Reviews Springer Netherlands 162/1-4(2011-12-01), 309-334 0038-6308 162:1-4<309 2011 162 11214 https://doi.org/10.1007/s11214-011-9811-y text/html Onlinezugriff via DOI 1 review-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11214-011-9811-y text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Lundin Rickard Swedish Institute of Space Physics, Teknikhuset, 90187, Umea, Sweden aut NATIONALLICENCE 773 0- Space Science Reviews Springer Netherlands 162/1-4(2011-12-01), 309-334 0038-6308 162:1-4<309 2011 162 11214 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer