[PEM12-P17] Variation of Schumann resonance at Kuju station during solar flares
Keywords:Schumann resonance, solar activity, solar flare
We examined the SR at Kuju, Japan (KUJ, M.Lat. = 23.4 degree, M. Lon. = 201.0 degree) by comparing solar X-ray and EUV flux. The data of X-ray and EUV flux were obtained by the GOES series of the satellites on a geostationary orbit and the SEM/SOHO at the Lagrangian point L1, respectively. Solar flare on 23 October 2003 was accompanied with the variation of SR parameters. The X-ray in 0.05-0.3 nm wave bands and EUV flux in 0.1-50 nm wave bands started to increase around 08:30 UT and reached the maximum value within about ten minutes. At the time, second mode of SR (SR2) frequencies in H (horizontal northward) and D (horizontal eastward) components also increased. The timing of peaks of SR2 frequencies coincided with EUV flux than X-ray. Since EUV contributes the most to ionization of Earth’s ionosphere, the variation of the SR frequency seems to reflect the electron density in the ionospheric D-region during the solar flare.