DMSP/GPS observations of intense ion upflow in the midnight polar ionosphere associated with the SED plume during a super geomagnetic storm

Abstract

We report observations from the GPS TEC and DMSP F‐15 satellite showing that a very strong upward field‐aligned (FA) plasma velocity and flux at F‐region heights in the auroral zone/polar cap boundary during a passage of the polar tongue of ionization (TOI) full of storm‐enhanced density (SED) materials occurred in the event of the super geomagnetic storm on Nov. 20, 2003. The upward FA ion velocities in excess of 460 m/s are obtained from observations of the DMSP F‐15 satellite. With enhancements of the plasma density caused by the TOI, FA ion fluxes are estimated to about 1.2 × 1014 ions m−2s−1, which are comparable to those observed by the ground‐based radar in the polar cusp. Therefore, during the super geomagnetic storm a s SED can cause a TOI plume at F region altitudes, which leads to a strong upward ion flux reaching 1–2 orders of magnitude larger than that of the typical flux at midnight auroral zone/polar cap boundary. Through estimations of the influence of those upflow ions associated with SED plumes on the development of the super storm, our result suggests that the midnight auroral zone/polar cap boundary becomes an important source to directly provide rich O+ to the ring current during super geomagnetic storms.