Generation of ELF waves during HF heating of the ionosphere at midlatitudes

Abstract

Modulated high‐frequency radio frequency heating of the ionospheric F region produces a local modulation of the electron temperature, and the resulting pressure gradient gives rise to a diamagnetic current. The oscillations of the diamagnetic current excite hydromagnetic waves in the ELF range that propagate away from the heated region. The generation of the waves in the 2–10 Hz range by a modulated heating in the midlatitude ionosphere is studied using numerical simulations of a collisional Hall‐magnetohydrodynamic model. To model the plasma processes in the midlatitude ionosphere the Earth's dipole magnetic field and typical ionospheric plasma parameters are used. As the hydromagnetic waves propagate away from the heated region in the F region, the varying plasma conditions lead to changes in their characteristics. Magnetosonic waves generated in the heating region and propagating down to the E region, where the Hall conductivity is dominant, excite oscillating Hall currents that produce shear Alfvén waves propagating along the field lines into the magnetosphere, where they propagate as the electromagnetic ion cyclotron (EMIC) and whistler waves. The EMIC waves propagate to the ion cyclotron resonance layer in the magnetosphere, where they are absorbed.

The Generation of ULF/ELF/VLF Waves in the Ionosphere by Modulated Heating

“…Based on the cold plasma model, Eliasson et al [69] constructed the numerical model of ELF/ULF waves excited by the ICD method, as well as the propagation model of MS waves and ELF/ULF waves. By considering the characteristics of the magnetic field and radio wave propagation in the mid-latitude ionosphere, Sharma et al [70] studied the excitation of ELF waves by the ICD method in the mid-latitude region and its propagation in the ionosphere and magnetosphere. Xu et al [71] studied the generation and propagation of ULF waves modulated by the ICD mechanism under different background ionospheric parameters and modulation frequencies through numerical simulation.…”

Tunable, Electrically Small, Inductively Coupled Antenna for Transportable Ionospheric Heating

“…Extremely low frequency wave generation in the ionosphere can be achieved with an ERP of 80 dBW (Sharma et al, ). To generate this power level a small 4 × array of ESAs on a steel barge with a gain of 20.4 dBi is sufficient.…”

Pitch angle scattering of relativistic electrons near electromagnetic ion cyclotron resonances in diverging magnetic fields

“…A collisional Hall-MHD model was developed by Eliasson et al (2012) (see also Sharma et al (2016) for polar coordinates), where plasma conductivities and dielectric constants were derived from the electron and ion momentum equations. We here slightly modify the formulation of Eliasson et al (2012) to include multiple ion species.…”