Sökning: "atmospheric escape"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden atmospheric escape.

  1. 1. Ion escape from Mars : measurements in the present to understand the past

    Författare :Robin Ramstad; Stas Barabash; Yoshifumi Futaana; David Brain; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mars; escape; solar wind; evolution; CME; coupling; plasma; atmosphere; Space Physics; rymdfysik;

    Sammanfattning : Present-day Mars is a cold and dry planet with a thin CO2-dominated atmosphere comprising only a few ­­­mbar pressure at low altitudes. However, the Martian surface is marked with valley networks, hydrated mineral clays, carbonates and the remains of deltas and meandering rivers, i.e. LÄS MER

  3. 2. Escape to space or return to venus : ion flows measured by venus express

    Författare :Moa Persson; Yoshifumi Futaana; Hans Nilsson; Maria Hamrin; Dmitrij Titov; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Venus; water; escape; planetary physics; oxygen; O ; hydrogen; H ; ions; space physics; space plasma physics; Venus Express; ASPERA-4; IMA; spacecraft measurements; rymd- och plasmafysik; Space and Plasma Physics;

    Sammanfattning : The present-day Venusian atmosphere is crushingly dense, extremely hot and arid. Yet, in its early history, Venus presumably had a massive amount of water, which, if spread evenly over the surface, provided a water depth of 10s to 100s of meters. Therefore, over the course of the atmospheric evolution, the water must have been removed from Venus. LÄS MER

  4. 3. Low-Energy Ion Escape from the Terrestrial Polar Regions

    Författare :Erik Engwall; Anders I. Eriksson; Mats André; Thomas Moore; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; space physics; ion outflow; polar wind; auroral upflows; atmospheric escape; magnetotail lobes; spacecraft wake; electric field measurements; Geocosmophysics and plasma physics; Geokosmofysik och plasmafysik; Space and Plasma Physics; rymd- och plasmafysik;

    Sammanfattning : The contemporary terrestrial atmosphere loses matter at a rate of around 100,000 tons per year. A major fraction of the net mass loss is constituted by ions, mainly H+ and O+, which escape from the Earth’s ionosphere in the polar regions. LÄS MER

  5. 4. Ion escape from Mars

    Författare :Qi Zhang; Mats Holmström; Xiao-Dong Wang; Shahab Fatemi; Hans Nilsson; David Andrews; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : When the solar wind reaches the Mars obstacle, mass loading by planetary ions slows down the solar wind and raises the bow shock. The Martian atmosphere is undergoing the a scavenging by the solar wind without the protection of a global magnetic field. Atmospheric escape is an important process for the evolution of the Martian climate. LÄS MER

  7. 5. O+ outflow during geomagnetic storms observed by Cluster satellites

    Författare :Audrey Schillings; Hans Nilsson; Stephan Buchert; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Atmosfärsvetenskap; Atmospheric Science;

    Sammanfattning : The region of space dominated by the Sun's magnetic field is called the heliosphere. It envelops the entire solar system including Earth. Therefore, a strong coupling exists between the Sun and our planet. LÄS MER