Generation of artificial ULF/ELF electromagnetic emission in the
ionosphere by horizontal ground-based current system
Abstract
The feasibility of detection of electromagnetic response in the upper
ionosphere to ground large-scale ultra-low-frequency (ULF) and
extremely-low-frequency (ELF) transmitters by low-Earth orbit (LEO)
satellites is considered. As an example of such transmitters, we
consider the ZEVS 82 Hz transmitter for submarine communication, FENICS
experiments with decommissioned electric power lines driven by 0.5–150
Hz generator, and industrial 50 Hz power transmission lines. We
numerically model the ULF/ELF wave energy leakage into the upper
ionosphere from an oscillating grounded linear current of a finite
length suspended above a high-resistive ground. A realistic altitudinal
profile of the plasma parameters has been reconstructed with the use of
the IRI ionospheric model. For the ZEVS transmitter powered by 200 A
current the modeled amplitudes of electromagnetic response can reach in
the upper nightside ionosphere up to
60~$\mu$V/m and 6 pT. The assumption of
an infinite source scale overestimates the ionospheric response by a
factor of $\sim$6 as compared with realistic scale 60
km of the ZEVS transmitter. Unbalanced 50 Hz current of 10 A in
large-scale ($>100$~km) power
transmission lines can produce the electric response in the upper
ionosphere that is sufficient to be detected by electric sensors at LEO
satellite. The stimulation of artificial Pc1 pulsations (0.5 Hz) with
amplitudes $\sim1$~pT and
$\sim10$~$\mu$V/m by
large-scale decommissioned power lines is possible with driving current
$>120$~A.