Solar-flare effects on ionospheric electrodynamics

Tuesday, March 20, 2012

The sudden increase of X-ray and extreme ultra-violet irradiance during flares increases the density of the ionosphere through enhanced photoionization. Model simulations showed that additional ionospheric changes come from electrodynamics, with a change in the vertical E×B drift in the magnetic equatorial region playing a significant role.

The figure shows horizontal maps of the ionosphere responses to the X17 flare that occurred on October 28, 2003 at 11:10 UT, about 20 minutes after the peak of the flare. (a) change of total electron content (TEC); (b) change of peak ionospheric density NmF2; (c) change of the height of the peak density hmF2; and (d) rate of change of electron density due to vertical E×B drifts at pressure level +2 (approximately 250 km altitude). Also plotted in the figure are the terminator and magnetic equator.

Reference: Qian, L., A. B. Burns, S.C. Solomon, and P.C. Chamberlin (2012a), Solar flare impacts on ionospheric electrodynamics, Geophys. Res. Lett., 39, L06101, doi:1019/2012GL051102.