[1] The ELF measurements in Russian observatories Lovozero (the Kola Peninsula) and Lekhta (Karelija) during the solar proton event of 14 July 2000 show the decrease of frequencies of the first and second Schumann resonance modes of $0.4 Hz and the increase of the first-mode bandwidth from 0.8 to 1.5 Hz. The solar X-ray burst, preceding the proton precipitation, is accompanied by the increase of the first-mode frequency. Approximate formulas for frequencies and qualities of the two first modes are found for a two-layer model of the Schumann resonator (SR). The changes of the SR parameters are a response of the Earth-ionosphere resonator to large-scale disturbances of the polar ionosphere.

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[1] Variations of the first mode Schumann resonance frequency in the Kola Peninsula and of the first and second mode frequencies in Kamchatka during seven days of MarchApril 2001, when the intensive solar X-ray bursts occurred, are studied with 5 min averaging. All X-ray bursts were accompanied by $0.2 Hz increase in the first mode frequency, at least in one of the magnetic components. Duration of the increases coincided with that of the bursts. For the second mode the increase (in average by $0.3 Hz) was registered in most events, when the ELF noise level was not very high.

Abstract. The variations of the ®rst mode of Schumann resonance are analyzed using data from Kola peninsula stations during the solar proton event of 6 November 1997. On this day the intensive¯ux of energetic protons on GOES-8 and the 10% increase of the count rate of the neutron monitor in Apatity between 1220 and 2000 UT were preceded by a solar X-ray burst at 1155 UT. This burst was accompanied by a simultaneous increase of the Schumann frequency by 3.5%, and the relativistic proton¯ux increase was accompanied by 1% frequency decrease. These e ects are explained by changes of the height and dielectric permeability of the Earth-ionosphere cavity.

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[1] In the first part of our paper, we consider the pattern of geomagnetic pulsations in the Pc5 range in the North European area, based on an event of 19 January 2005. Intense pulsations, observed in Lovozero at Kola Peninsula, were accompanied by auroras north of the station, recorded by an all-sky TV camera. In the second part, we consider the global pattern of amplitudes and phases of geomagnetic pulsations for this event, which includes data from nearly conjugate stations and the magnetic data of GOES 10 and 12, confirming the quasi-stationary model for magnetic field distribution on the ground. In the event, the auroral luminosity oscillated with the same 5 min period as the magnetic field. Magnetic data from Scandinavia and data from North Europe riometers show analogous pulsations. The maximal intensity of geomagnetic pulsations in this region occurred near the pulsating aurora, but there was a reversal of pulsation polarity in the X-component. In the area of phase change the value of the Z-component is maximal. We suggest that geomagnetic pulsating variations, observed on the surface, are determined by Biot-Savart's law for a three-dimensional current system, the extra-ionospheric part of which is spatially coincident with auroral electron flux. The electric field in the ionosphere is found from the current continuity condition and the value of Pedersen conductivity. The directions to the pulsating current, calculated by using the magnetic data from Lovozero, are close to the directions of the auroral area. We also claim that this approach is applicable to all short periodic oscillations observed on the surface. Satellite data indicates the same periods, but with oscillations that appear to be poloidal on GOES10 and toroidal on GOES12, suggesting the traveling character of the wave.

[1] The diurnal variation of the frequency of the first Schumann resonance mode has been studied from three ELF observation sites located at Spitsbergen, the Kola Peninsula, and the Kamchatka Peninsula. The induction magnetometer measured ELF separately in two components: NS (north-south) and EW (east-west). The frequency variation is 0.2-0.3 Hz at all the observatories. The semidiurnal harmonics dominate in the frequency variation. The variation seems to be controlled by the local time (LT) rather than by the universal time (UT). The frequency of the NS component has maxima approximately at 0700 and 1900 LT. The diurnal variation of the frequency of the EW component reveals the antiphase behavior so that the maximum in the EW component frequency occurs at $0100 and 1300 LT.

Abstract. The variations of the ®rst mode of Schumann resonance are analyzed using data from Kola peninsula stations during the solar proton event of 6 November 1997. On this day the intensive¯ux of energetic protons on GOES-8 and the 10% increase of the count rate of the neutron monitor in Apatity between 1220 and 2000 UT were preceded by a solar X-ray burst at 1155 UT. This burst was accompanied by a simultaneous increase of the Schumann frequency by 3.5%, and the relativistic proton¯ux increase was accompanied by 1% frequency decrease. These eects are explained by changes of the height and dielectric permeability of the Earth-ionosphere cavity.