Equivalent ionospheric currents for the 5 December 2006 solar flare effect determined from spherical cap harmonic analysis

Abstract

In this paper we analyze the prompt solar flare effect (SFE) associated to a strong X-ray flare that occurred on 5 December 2006 by using spherical cap harmonic analysis applied to the variations recorded in the European magnetic observatories network. The regional model allows the simultaneous modeling in space and time of the ionospheric equivalent current system responsible for the SFE, as well as for the regular diurnal variation SR on that day. It is found that the SFE equivalent current system does not form as an enhancement of the SR system. Its focus is distinct from that of the S R, and it is located between 3 and 10° higher in latitude and circa 40 min later in local time.