Whistler wave radiation from a pulsed loop antenna located in a cylindrical duct with enhanced plasma density

Abstract

Pulsed radiation from a loop antenna located in a cylindrical duct with enhanced plasma density is studied. The radiated energy and its distribution over the spatial and frequency spectra of the excited waves are derived and analyzed as functions of the antenna and duct parameters. Numerical results referring to the case where the frequency spectrum of the antenna current is concentrated in the whistler range are reported. It is shown that under ionospheric conditions, the presence of an artificial duct with enhanced density can lead to a significant increase in the energy radiated from a pulsed loop antenna compared with the case where the same source is immersed in the surrounding uniform magnetoplasma. The results obtained can be useful in planning active ionospheric experiments with pulsed electromagnetic sources operated in the presence of artificial field-aligned plasma density irregularities that are capable of guiding whistler waves.

Radiation From a Dipole Antenna Located Outside a Cylindrical Density Depletion in a Magnetoplasma Under Resonance Scattering Conditions

“…It should be noted that the problem of excitation of cylindrical plasma structures by given electromagnetic sources has in principle been discussed in the literature. In particular, this problem has been considered in application to determining the excited field in the presence of guiding magnetized plasma structures such as radio-frequency helicon discharges [50][51][52], magnetic-field-aligned density ducts in space and laboratory plasmas [19,46,[53][54][55][56][57], and very low-frequency plasma-waveguide antenna systems [58,59]. However, in all the above-mentioned applications, the electromagnetic sources are usually located inside or on the boundary of a cylindrical plasma object.…”

Scattering of an Obliquely Incident Plane Electromagnetic Wave by a Magnetized Plasma Column: Energy Flow Patterns at Plasmon Resonances

“…In the optical range, this interest is stimulated by promising applications of systems with nanosized gyrotropic elements [2], photonic crystals on the basis of gyrotropic scatterers [3], and nonreciprocal devices containing magnetooptic materials [4,5]. In the RF range, the corresponding analysis is needed for consideration of the excitation and propagation of electromagnetic waves in the presence of artificial plasma density irregularities aligned with an external static magnetic field [6], especially if the excitation source is located outside such a plasma structure, rather than inside of it [7] or on its surface [8]. Since the understanding of the features of wave diffraction by gyrotropic cylindrical structures often requires knowledge of the field distribution near scatterers, the problem of finding the near-zone scattered fields turns out to be very topical.…”