An updated theory of the polar wind |
| |
| Institution: | 1. Max Planck Institute for Plasma Physics, Boltzmannstrasse 2, 85748 Garching, Germany;2. Technical University of Munich, Department of Physics, James-Franck-Strasse 1, 85748 Garching, Germany;3. Technical University of Munich, Department of Mathematics, Boltzmannstrasse 3, 85748 Garching, Germany;1. European Space Research and Technology Centre (ESTEC), European Space Agency, Keplerlaan 1, 2201AZ Noordwijk, Netherlands;2. European Space Astronomy Centre, (ESAC), European Space Agency, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Cañada, Madrid, Spain;1. Marie Curie fellow of the Istituto Nazionale di Alta Matematica, DISIM, Università degli Studi dell''Aquila, via Vetoio n. 1, 67100 L''Aquila, Italy;2. School of Mathematics, Georgia Institute of Technology, 686 Cherry St. Atlanta, GA 30332, USA;1. Astronomical Institute, University of Bern, Switzerland;1. National Observatory of Athens, Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, Penteli 15236, Greece;2. Space Environment and Radio Engineering Group (SERENE), University of Birmingham, B15 2TT, Birmingham, UK;3. Department of Physics, University of New Brunswick, PO Box 4440, Fredericton E3B 5A3 NB, Canada;4. Yonsei University, Department of Atmospheric Sciences, Seoul 03722, South Korea;5. German Aerospace Center, 17235, Neustrelitz, Germany;6. Institute of Meteorology and Water Management - National Research Institute, 01-673, Warsaw, Poland;7. Faculty of Civil and Environmental Engineering, Gdansk University of Technology, 80-233, Gdansk, Poland;8. Instituto de Astrofísica e Ciências do Espaço, Physics Department, University of Coimbra, 3040-004, Coimbra, Portugal;9. Instituto de Astrofísica e Ciências do Espaço, Department of Earth Sciences, University of Coimbra, 3040-004, Coimbra, Portugal;10. Department of Physics, University of Oslo, PO Box 1048 Blindern 0316, Oslo, Norway |
| |
| Abstract: | The ‘classical’ polar wind is an ambipolar outflow of thermal plasma from the terrestrial ionosphere at high latitudes. As the plasma escapes along diverging geomagnetic flux tubes, it undergoes four major transitions, including a transition from chemical to diffusion dominance, a transition from subsonic to supersonic flow, a transition from collision-dominated to collisionless regimes, and a transition from a heavy to a light ion. A further complication arises because of horizontal convection of the flux tubes owing to magnetospheric electric fields. Recent modelling predictions indicate that the polar wind has the following characteristics: (1) The ion and electron distributions are anisotropic and asymmetric in the collisionless regime; (2) Elevated electron temperatures ( ∼ 10,000 K) act to produce significant escape fluxes of suprathermal O+ ions; (3) The interaction of the hot magnetospheric and cold ionospheric electron populations leads to a localized (double layer) electric field which accelerates the polar wind ions; (4) A time-dependent expansion produces suprathermal ions; and (5) Large perturbations lead to the formation of forward and reverse shocks. These and other results are reviewed. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
