Effect of Solar Flares on the Schumann-Resonance Frequences

Resumo

We present the results of analyzing the response of the Schumann-resonance frequencies to the Xray solar flares. A special technique, by which a sharp variation that is present in all the resonant modes, but is hidden by regular variations combined with stochastic fluctuations is singled out using the weighted average frequency, has been developed. On the basis of comparison of the response shape and the flare intensity, the parameters of the statistical relationship between the frequency variations and the X-ray radiation intensity were analyzed and determined for the nonlinear regression model. It has been shown that an increase in the resonant frequency is proportional on the average to the logarithm of the X-ray radiation intensity to the power of 1.7. The magnitude of changes in the cavity frequency is related with the corresponding changes in the characteristic “magnetic” height of the conductivity profile of the lower ionosphere and compared with the results of the independent analysis performed by measuring VLF radio signals.