Penetration of the convection and overshielding electric fields to the equatorial ionosphere during a quasiperiodic DP 2 geomagnetic fluctuation event

Details Penetration of the convection and overshielding electric fields to the equatorial ionosphere during a quasiperiodic DP 2 geomagnetic fluctuation event Penetration of the convection and overshielding electric fields to the equatorial ionosphere during a quasiperiodic DP 2 geomagnetic fluctuation event

May 2010

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010jgra..11505209k&link_type=abstract

Journal of Geophysical Research, Volume 115, Issue A5, CiteID A05209

Other

4

Ionosphere: Current Systems (2721), Ionosphere: Electric Fields (2712), Ionosphere: Equatorial Ionosphere, Ionosphere: Ionospheric Disturbances, Ionosphere: Ionosphere/Magnetosphere Interactions (2736)

Scientific paper

The convection electric field penetrates to the equatorial ionosphere with no significant shielding during DP 2 fluctuation events with periods of 30-60 min (Nishida, 1968) and even during the main phase of a storm that continues over several hours (Huang et al., 2007). On the other hand, shielding becomes effective in 20 min during the substorm growth phase (Somayajulu et al., 1987), and in 1 h during the main phase of a storm (Kikuchi et al., 2008a). To clarify the relative contributions of the convection and shielding electric fields at middle to equatorial latitudes, we analyzed an equatorial DP 2 fluctuation event of 30 min duration, using magnetometer data, Super Dual Auroral Radar Network (SuperDARN) convection maps, and electric potentials calculated with the comprehensive ring current model (CRCM). The equatorial DP 2 fluctuations were found to be caused by alternating eastward electrojets (e-EJ) and westward electrojets (w-EJ) in the equatorial ionosphere, which were caused by the southward and northward interplanetary magnetic field, respectively. Using the SuperDARN convection map, we further show that the e-EJ is associated with large-scale two-cell convection vortices, while the w-EJ accompanies reverse flow vortices equatorward of the two-cell vortices. With the aid of the CRCM, we suggest that the reverse flow vortices were associated with the region 2 field-aligned currents (R2 FACs) that caused overshielding at the equator. We think it reasonable that the overshielding electric field could appear at middle to equatorial latitudes irrespective of the period of fluctuations as the region 1 FACs decrease their intensity. This scenario well explains both DP 2 fluctuations with periods of 30-60 min and continuous penetration for several hours during the main phase of storms.

Affiliated with

Also associated with

No associations

Rating

Penetration of the convection and overshielding electric fields to the equatorial ionosphere during a quasiperiodic DP 2 geomagnetic fluctuation event does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Penetration of the convection and overshielding electric fields to the equatorial ionosphere during a quasiperiodic DP 2 geomagnetic fluctuation event, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Penetration of the convection and overshielding electric fields to the equatorial ionosphere during a quasiperiodic DP 2 geomagnetic fluctuation event will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-794691