Spatial structure of the electromagnetic field inside the ionospheric Alfvén resonator excited by atmospheric lightning activity

Abstract

[1] We have theoretically estimated ULF spectra on the ground and at ionospheric altitudes in the frequency range of the ionospheric Alfvén resonator (IAR). The IAR has been considered to be excited either by a separate lightning stroke or stochastic global thunderstorm activity. The spectra of both horizontal magnetic and electric components are shown to reveal the spectral resonant structure in the upper ionosphere. The IAR excitation for different ionospheric conditions has been compared. The IAR eigenfrequencies latitudinal inhomogeneity results in the smoothing and shift of the spectral resonance structure. The feasibility of the IAR signature detection by low-orbiting satellites with magnetic or electric sensors is discussed.Citation: Plyasov, A. A., V. V. Surkov, V. A. Pilipenko, E. N. Fedorov, and V. N. Ignatov (2012), Spatial structure of the electromagnetic field inside the ionospheric Alfvén resonator excited by atmospheric lightning activity,

An unusual sequence of sprites followed by a secondary TLE: An analysis of ELF radio measurements and optical observations

“…Plyasov et al . [] showed that the IAR spectra produced by a single lightning discharge can be observed on the ground and are present only in the radial component of the magnetic field. Our measurements provide evidence in favor of this theory.…”

IAR signatures in the ionosphere: Modeling and observations at the Chibis-M microsatellite

“…Though the C/NOFS electric field sensor had a very high sensitivity in the ULF/ELF frequency range, no regular long-lasting IAR features, similar to typical ground signatures, have been reported. Chibis-M detected sporadic IAR signatures which could be excited by a single intense lightning stroke, but with amplitudes about order of magnitude larger than that observed by C/NOFS and theoretically predicted by Plyasov et al (2012). Seemingly, only discharges with intensities much higher than typical, e.g., CG þ strokes (Shalimov and Bösinger, 2008), can excite IAR modes in the upper ionosphere.…”

“…In the ULF range, M(f) practically does not depend on frequency, and can be estimated as M ¼Iτd, where I is the amplitude of continuing current at the final stage of a stroke, d is the length of a current channel, and τ is the duration of continuing current. Using the CG-stroke parameters I∼0.5 kA, d¼ 4 km, and τ¼6 ms, such that M¼ 12 C km, Plyasov et al (2012) estimated with a simplified multi-layered model the excitation rate of Alfvén waves by a typical vertical atmospheric electric discharge. According to their calculations, a peak spectral amplitude in the nighttime upper ionosphere (400 km) by an isolated stroke at distance R¼10 3 km at IAR resonant frequency f¼ 0.5 Hz can reach ∼0.05 (μV/m)/Hz 1/2 .…”

“…However, the ionospheric response involving the IAR excitation is expected to be more significant. Indeed, Plyasov et al (2012), using a simplified multi-layered plane model, estimated analytically the IAR excitation rate by an atmospheric electric discharge, and claimed the possibility of IAR detection in the midand high-latitude ionosphere by modern electric or magnetic sensors onboard low-orbiting satellites. The effective leakage of 50/60 Hz emission from industrial power lines found by microsatellite Chibis-M also indicates an effective coupling of near-surface ULF-ELF emitters with emissions in the upper ionosphere (Dudkin et al, 2015).…”

Use of the International Reference Ionosphere 2012 model to calculate emission frequency scale of the ionospheric Alfvén resonator

“…The effective mass of the ions at each height level is determined by adding the masses of the ions with a weight corresponding to the relative concentration of ions at a given altitude. In contrast to Lysak (1991); Demekhov et al (2000) and Plyasov et al (2012), we do not develop a theory of the IAR to compare theoretical and experimental spectral characteristics of the IAR emission. Instead, we compare the observational data with the results of Df calculations based on formula (1).…”