Transionospheric attenuation of 100 kHz radio waves inferred from satellite and ground based observations

Abstract

[1] Around fifty LORAN (LOng RAnge Navigation) transmitters in the northern hemisphere currently launch continuously pulsed 100 kHz radio waves into the Earth's atmosphere for marine navigation. It is discovered that the 100 kHz radio waves from the LORAN transmissions can be detected by the DEMETER satellite at an altitude of $660 km above the transmitters. These novel electric field measurements in space enable the determination of the nocturnal transionospheric attenuation by comparison with ground based electric field measurements. The electric field measurements on the satellite indicate that the nocturnal transionospheric attenuation of 100 kHz radio waves from LORAN transmissions is equivalent to a nocturnal subionospheric attenuation of the 100 kHz radio waves at a distance of $7 -9 Mm. The radio waves exhibit an average subionospheric attenuation of $5 dB/Mm and it is concluded that the nocturnal transionospheric attenuation of 100 kHz radio waves is $35-45 dB. This result enables future space missions to quantify the intensity of lightning discharges associated with transient luminous events and terrestrial g-ray flashes. Citation: Fullekrug, M., M. Parrot, M. Ash, I. Astin, P. Williams, and R. Talhi (2009), Transionospheric attenuation of 100 kHz radio waves inferred from satellite and ground based observations, Geophys. Res. Lett., 36, L06104,

Relativistic runaway breakdown in low‐frequency radio

“…Another interesting question is if the consecutive broadband pulses from relativistic runaway breakdown can be observed from space by radio satellites such as TARANIS [ Blanc et al , 2007]. Initial observations indicate that the electromagnetic radiation at ∼100 kHz is attenuated by ∼40 dB during the propagation through the ionosphere [ Füllekrug et al , 2009]. The experimental results reported here will thereby enable a quantitative estimate of the instrumental sensitivity required on radio satellites to record the electromagnetic signatures of relativistic runaway breakdown from space.…”

Relativistic electron beams above thunderclouds

“…However, these processes remained sub-visual in the optical observations reported in this work, and it is not clear why such a hypothetical process would emit low frequency electromagnetic radiation while the sprite itself does not. It is interesting to note that the low frequency electromagnetic radiation reported here can be observed in space as a result of its transionospheric propagation (Füllekrug et al, 2011(Füllekrug et al, , 2009) and it may be associated with high frequency electromagnetic radiation (Parrot et al, 2008).…”

Subionospheric propagation and peak currents of preliminary breakdown pulses before negative cloud‐to‐ground lightning discharges

“…With this data set, we have used a nonlinear least squares method to estimate parameters of a model of the electric field amplitude E at a horizontal distance d from the source, based on the planar geometry of emitted radiation, where the coefficient A (in V/m) represents the electric field amplitude at a distance of 100 km from the source lightning. α × 20 dB gives the amplitude attenuation in decibels per 100 km, representing a simplified form of the wave propagation constant [e.g., Fullekrug et al ., ]. The resulting nonlinear fits for all 10 analyzed RS pulses are plotted as solid lines in Figure a.…”