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Velocity of particles in the Ring Current

  1. Aug 27, 2009 #1
    How fast are the electrons and the ions in the Ring Current (in the magnetosphere?)
  2. jcsd
  3. Sep 17, 2009 #2


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    Bjarne: “What is the velocity of a particle in the ring current?”

    You have come to the right place to ask your question and to expect an answer. Also, welcome to the world of Magnetohydrodynamics (MHD), where some folks spend their entire career studying the complexities!

    The combination of plasma and electric fields in the earth’s magnetosphere allows several electric currents to flow:
    1. the magnetopause current
    2. the tail current
    3. the ring current
    4. Birkeland (field-aligned) currents

    Since particles making up the ring current are mainly protons, oxygen ions, alpha particles, and electrons it is difficult or impossible to say what individual velocities they have. Charged particles spiral along magnetic field lines in helical orbits. Negative and positive particles travel in opposite directions. Geophysicists usually speak about the energy of the particles, or the “energy density” of the overall ring current. This current has “quiet day values” and increases during magnetic storms, when there is an injection of energy by particles from the solar wind. This is called a “Magnetic Storm”. The magnetic field that the ring current generates interacts with the geomagnetic field and that compresses the magnetosphere, so the ring current density can be detected (indirectly) by magnetometers located on earth and in orbiting satellites.

    Reference: “The solar-terrestrial environment”, J. K. Hargreaves, Cambridge U. Press

    One range of energy of the particles in the ring current (given in Wikipedia) is from 0.05 MeV to 1 MeV, but it doesn’t say which particles that refers to.

    I suggest you use Wikipedia to start your search, then try the references therein. You may then go to arXiv and search for technical papers on the subject…just type in your search terms and plow through the results.

    For a good description of the ring current see:


    Surely we have Advisors, Mentors, Contributors, and others here in PF who are more qualified to answer your question more professionally than this.
    Last edited: Sep 17, 2009
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