Line splitting in the Schumann resonance oscillations

Abstract

[1] We discuss detection of line splitting in the global electromagnetic (Schumann) resonances. The lifting of resonance degeneracy is usually not visible in the ordinary power spectrum of either the electric or magnetic field components since splitting is small in comparison with the natural width of the resonance lines. Splitting may be detected by exploiting the spatial structure of the fields and/or the elliptical polarization of the magnetic field. The spatial properties were utilized in synchronous and coherent measurements of the vertical electric field at two longitudinally separated observatories. The results were attributed to line splitting. An alternative interpretation was also advanced that takes into account the source-receiver separation. The lifting of degeneracy also appears as a frequency-dependent elliptical polarization of the horizontal magnetic field vector, which has been found experimentally. We compare measurement and computational data, and their reciprocity proves the detection of Schumann resonance line splitting.

Schumann Resonance for Tyros

“…7.3 illustrates the model results for the spectral amplitude of the field component H u (see Nickolaenko and Sentman 2007). 7.3 illustrates the model results for the spectral amplitude of the field component H u (see Nickolaenko and Sentman 2007).…”

Electromagnetic wave propagation in the surface‐ionosphere cavity of Venus

“…On the contrary, the major contribution to line splitting on Venus comes from day‐night asymmetry because the ionosphere is highly deformed and other contributions can be neglected in a first‐order approximation. Recent observations have shown evidence of line splitting (∼0.5 Hz) and amplitude variation of Schumann resonances of the Earth's cavity due to cavity asymmetry [ Sátori et al , 2007; Nickolaenko and Sentman , 2007]. According to the present model, eigenfrequency splitting for the Venus cavity is higher than for Earth because of not only larger cavity asymmetry but also higher Q‐factor.…”

Schumann Resonances as a Means of Investigating the Electromagnetic Environment in the Solar System

“…Yang et al (2006) employing the FDTD method have obtained similar results. Interestingly, all approaches predict similar eigenfrequencies, though the Nickolaenko and Rabinovich (1982) model halves the Q-factor. Simões et al (2008a), using a FEM algorithm and similar conductivity profiles, assessed the contribution of subsurface losses to the Q-factor; they found similar eigenfrequencies and Q-factors to those reported by Yang et al (2006) unless the surface conductivity is lower than 10 −5 -10 −4 S m −1 .…”

“…The environments of Titan, Europa, and Io are different and unique. Schumann resonance characteristics on Io have been estimated by Nickolaenko and Rabinovich (1982), though it is unlikely that they occur because the conductivity close to the surface is high leading to evanescent modes (Simões et al 2008a). Volcanoes might be an ELF source of electromagnetic energy on Io but wave attenuation prevents the development of resonant states.…”

“…In particular, the Venera 11 and 12 probes collected electric field data at very low frequencies (10-80 kHz) during their descent through the atmosphere. The first estimates of Schumann resonances for the Venus cavity were made by Nickolaenko and Rabinovich (1982). The major contribution of this work was to show that Schumann resonances are suitable for studying planetary electricity and can be used to infer lightning activity.…”