Numerical Simulation of Whistler Waves in Magnetized Plasma with Small-Scale Irregularities

Zudin, I. Yu.; Aidakina, N. A.; Gushchin, M. E.; Zaboronkova, T. M.; Korobkov, S. V.; Костров, А. В.

doi:10.1134/s1063780x17120078

Cited by 4 publications

(9 citation statements)

References 24 publications

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“…This pattern probably reveals the waveguide properties of the individual irregularities, and possibly the wave energy exchanges between them. A similar picture was obtained in whistlers' simulations with periodic density irregularities (Zudin et al, ).…”

Section: Numerical Simulations' Resultssupporting

confidence: 81%

“…In order to obtain the energy flow of the ducted waves, a procedure similar to that described in Zudin et al () is used. The energy flow parallel to B 0 is calculated by integrating the Poynting flux over x

normalΠ false(z false) = true \int_{- 2.5 km}^{2.5 km} S_{z} false(x, z false) d x,

where S z is the Poynting vector component along B 0 .…”

Section: Numerical Simulations' Resultsmentioning

confidence: 99%

“…In a recent paper (Zudin et al, ), the scattering of a whistler wave packet on a quasiperiodic sequence of planar (2D) density crests and troughs was studied owing to a numerical Finite Difference in Time‐Domain (FDTD) method. Specific properties of whistler ducting along the sets of density irregularities were revealed.…”

Section: Introductionmentioning

confidence: 99%

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Whistler Waves' Propagation in Plasmas With Systems of Small‐Scale Density Irregularities: Numerical Simulations and Theory

et al. 2019

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The propagation of whistler waves in a magnetized plasma containing multiple small-scale (100 m to 1 km) field-aligned irregularities of enhanced electron density is considered analytically and by means of numerical simulations. Such systems of irregularities can develop in the upper ionosphere during the generation of density ducts by high-frequency heating facilities and other types of active experiments. The simulation parameters are close to those of an active experiment where a whistler wave of 18 kHz emitted by a ground-based very low frequency (VLF) transmitter was received onboard the DEMETER satellite at 700 km above the SURA heater. The study reveals a number of remarkable properties of the VLF waves' propagation, including the existence of specific waveguide modes of the small-scale density structures and of a characteristic transverse size d 0 of the irregularities. Irregularities with small density enhancements around 10-20% and transverse sizes larger than d 0 ∼ 1 km can serve as separate waveguides for VLF waves. In their turn, single irregularities narrower than d 0 cannot be considered as individual ducting structures. Numerical simulations show that, for the analysis of the electromagnetic whistlers' propagation, a system of closely spaced irregularities with scales narrower than d 0 can be modeled by an equivalent ducting structure with a smoothed density profile. Such equivalent structure has the same ducting properties for whistlers and can be produced by averaging with a sliding window of a scale about d 0 the original density distribution.

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Section: Numerical Simulations' Resultssupporting

confidence: 81%

normalΠ false(z false) = true \int_{- 2.5 km}^{2.5 km} S_{z} false(x, z false) d x,

where S z is the Poynting vector component along B 0 .…”

Section: Numerical Simulations' Resultsmentioning

confidence: 99%

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Whistler Waves' Propagation in Plasmas With Systems of Small‐Scale Density Irregularities: Numerical Simulations and Theory

et al. 2019

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“…Therefore, there is no reason to believe that the enhancement of the VLF transmitter signal observed at the height of the DEMETER satellite orbit is associated with the pumping of small-scale irregularities by LH waves as a result of the conversion of electromagnetic VLF whistlers. Thus, effects observed in Rapoport et al (2010) should be associated with the scattering of whistlers into quasi-electrostatic resonance cone (not LH) waves, and probably with VLF waves' ducting by small-scale density crests and density depletions (Zudin et al, 2017(Zudin et al, , 2019.…”

Section: Ducting Of Whistlers By Small-scale Density Depletions In Sp...mentioning

confidence: 99%

“…To study whistler wave propagation along systems of irregularities with depleted plasma density we use a numerical model similar to that of our previous works (Zudin et al, 2017(Zudin et al, , 2019, based on the Finite Difference in Time-Domain (FDTD) method. The dynamics of the electromagnetic fields is described by the Maxwell's equations.…”

Section: Numerical Modelmentioning

confidence: 99%

Properties of Whistler Waves’ Ducting in Plasmas With Systems of Small‐Scale Density Depletions

Zudin,

Zaboronkova,

Gushchin

et al. 2023

JGR Space Physics

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The ducting of whistler waves by systems of small‐scale field‐aligned plasma density depletions is studied. Similarly to our previous paper (Zudin et al., 2019), we carry out analytical calculations and numerical simulations for the parameters of an active experiment in which very low frequency (VLF) whistler waves emitted by a ground‐based transmitter at a frequency of 18 kHz were received onboard the DEMETER satellite at 700 km above the SURA heating facility. Random‐sized density depletions with a level around 10 − 20% and perpendicular sizes ranging from 10 m up to about 300 m are considered. The properties of ducted waves are determined by the perpendicular size of individual depletions. Particularly, depletions with a width of more then d0 ∼ 100 m form separate ducting structures, i.e. coupled waveguides capable of exchanging energy by means of mode overlap. Depletions with a width of less than d0 ∼ 100 m form a common waveguide structure, whose properties are equivalent to those of a wider irregularity with a smoothed density profile. Two important differences are revealed in ducting properties of density depletions compared to density enhancements considered in (Zudin et al., 2019). First, depletions support highly oblique Gendrin mode waves, rather than quasi‐longitudinal whistlers as in the case of density enhancements. Second, the characteristic perpendicular size d0 ∼ 100 m of density depletions separating the regimes of “coupled waveguides’ and of “equivalent ducting structure’ with smoothed density profile is by an order of magnitude smaller than for density enhancements of the same 10 − 20% relative level.This article is protected by copyright. All rights reserved.

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Laboratory study of interaction of magnetoplasma irregularities produced by several radio-frequency heating sources

et al. 2018

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The dynamics of a group of narrow field-aligned plasma density irregularities is studied using the large-scale KROT plasma device. The chosen experimental conditions are similar to the conditions in the ionosphere of the Earth, where such irregularities develop under the impact of high-power, high-frequency radio waves. In our laboratory experiment, the irregularities are created by a set of rf antennas arranged in a row across the ambient magnetic field due to the heating of electrons and subsequent redistribution of the plasma. Near the heating sources, the irregularities have the form of a set of channels with reduced plasma density, which develop almost independently. At the same time, the relaxation time of a group of neighboring irregularities differs from that of each single irregularity. Evolution of density perturbations at the periphery of the heating region differs for a single irregularity and for a group of irregularities significantly. These effects are probably due to eddy currents excited by each of the irregularities in the background plasma, since narrow irregularities can develop in the “unipolar” thermal diffusion regime. The preliminary experimental results are consistent with the theoretical predictions of unipolar diffusion and excitation of eddy currents.

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Numerical Simulation of Whistler Waves in Magnetized Plasma with Small-Scale Irregularities

Cited by 4 publications

References 24 publications

Whistler Waves' Propagation in Plasmas With Systems of Small‐Scale Density Irregularities: Numerical Simulations and Theory

Whistler Waves' Propagation in Plasmas With Systems of Small‐Scale Density Irregularities: Numerical Simulations and Theory

Properties of Whistler Waves’ Ducting in Plasmas With Systems of Small‐Scale Density Depletions

Laboratory study of interaction of magnetoplasma irregularities produced by several radio-frequency heating sources

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