High-power ELF radiation generated by modulated HF heating of the
ionosphere can cause Earthquakes, Cyclones and localized heating.

1. Introduction

Generating electromagnetic radiation
at extremely-low frequencies is difficult
because the long wavelengths require long
antennas, extending for hundreds of
kilometers. Natural ionospheric currents
provide such an antenna if they can be
modulated at the desired frequency [1-6]. The
generation of ELF electromagnetic radiation
by modulated heating of the ionosphere has
been the subject matter of numerous papers
[7-13].
In 1974, it was shown that ionospheric
heater can generate ELF waves by heating
the ionosphere with high-frequency (HF)
radiation in the megahertz range [7]. This
heating modulates the electron’s temperature
in the D region ionosphere, leading to
modulated conductivity and a time-varying
current, which then radiates at the
modulation frequency.

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