Inertial currents and substorm onsets
1996 (English)In: European Space Agency, (Special Publication) ESA SP-389, ISSN 03796566, 447-452 p.Article in journal (Refereed) Published
When magnetic field lines are sufficiently stretched during the substorm growth phase, in the equatorial plane the earthward ExB ion drift velocity can become comparable to the ion gyration velocity. Under these conditions inertial currents can become quite important. Using a two-dimensional model we find that O+ ions injected from the ionosphere into the equatorial plane at high latitudes will drift eastward at radial distances less than -10 RE because the inertial drift dominates and westward at distances closer to the earth because the magnetic gradient drift dominates. The inertial eastward drift gives rise to a current which in terms of JxB is consistent with the convective deceleration of the earthward drift velocity due to higher values of B. Similarly, momentum balance requires that the convective acceleration of the westward drift velocity should be consistent with a tailward inertial current. Therefore, an equatorial current wedge system with eastward and tailward current components naturally arises from the ion dynamics. In a future paper a three-dimensional treatment will determine whether curvature drift masks the eastward inertial drift of the oxygen ions.
Place, publisher, year, edition, pages
1996. 447-452 p.
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:kth:diva-92934OAI: oai:DiVA.org:kth-92934DiVA: diva2:514502
cited By (since 1996) 0 NR 201408052012-04-102012-04-072012-04-10Bibliographically approved