Electrodynamics of Density Ducts in Magnetized Plasmas

Kondrat'ev, I. G.; Kudrin, Alexander V.; Zaboronkova, T. M.

doi:10.1201/9780367810474

Cited by 24 publications

(48 citation statements)

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“…According to the energy conservation law, the power transported through the waveguide cross‐section tends to be constant or weakly decaying. As the waves transported by the ducts with density enhancements are leaky modes (Kondrat'ev et al, ), the field inside the duct should decay exponentially over a distance larger than the whistler wavelength. According to Figure , the ducted propagation of whistlers is observed at

z ≳ 25

km.…”

Section: Numerical Simulations' Resultsmentioning

confidence: 99%

“…Note that only the extraordinary (whistler) wave propagates in the frequency band , while the ordinary wave is evanescent. The dispersion law of monochromatic (

\propto \exp ((), 2 π i f t)

) whistlers can be written as follows (Kondrat'ev et al, ):

p^{2} = ε - \frac{1}{2} ((), 1 + \frac{ε}{η}) q^{2} + {([], \frac{1}{4} ((), 1 - \frac{ε}{η}) q^{4} - \frac{g^{2}}{η} q^{2} + g^{2})}^{\frac{1}{2}},

where p = k z / k 0 , q = k ⊥ / k 0 and k 0 =2 πf / c ; k z and k ⊥ are the parallel and the perpendicular (with respect to the z ‐axis) components of the wave vector k , and the z ‐axis is directed along the ambient magnetic field B 0 ; ε , η , and g are the elements of the dielectric tensor

\overset{ε}{true} = ((), \begin{matrix} center center center \\ array ε & array - i g & array 0 \\ array i g & array ε & array 0 \\ array 0 & array 0 & array η \end{matrix}) .

…”

Section: General Properties Of Whistler Wavesmentioning

confidence: 99%

“…Thus, inside the duct, the modes are the superposition of two propagating waves. Outside the duct, the modes are the superposition of evanescent waves and resonance cone waves with the same parallel wave number (Kondrat'ev et al, ). Note that the leakage of whistlers' energy is associated with the quasi‐electrostatic parts of the leaky modes.…”

Section: General Properties Of Whistler Wavesmentioning

confidence: 99%

“…In order to model 3‐D configurations, let us recall the properties of the whistler modes guided by a cylindrical density duct. The modes guided by a step‐like density profile of radius a can be described via the parallel components of the electric and magnetic fields (Kondrat'ev et al, ):

\begin{matrix} alignleft \\ align-1 \{\begin{array}{c} E_{z, m} \\ B_{z, m} \end{array}\} & align-2 = - \exp [- i (m ϕ \pm k_{0} p z)] \sum_{α = 1}^{2} \{\begin{array}{c} i n_{α}^{'} false/ V^{'} \\ c^{- 1} \end{array}\} A_{α} q_{α}^{'} J_{m} (k_{0} q_{α}^{'} ρ), if ρ < a, \\ align-1 \{\begin{array}{c} E_{z, m} \\ B_{z, m} \end{array}\} & align-2 = \exp [- i (m ϕ \pm k_{0} p z)] \sum_{α = 1}^{2} \{\begin{array}{c} i n_{α} false/ V_{0} \\ c^{- 1} \end{array}\} C_{α} s_{α} K_{m} (k_{0} s_{α} ρ), if ρ > a, \end{matrix}

where A α and C α are constants; J m and K m are the Bessel function and the modified Bessel function of the second kind, respectively; and m is the azimuthal number ( m =0,1,2,…); ρ is the radial coordinate, and ϕ is the azimuthal angle. Outside the duct, the field is composed of evanescent whistler mode waves (

\propto K_{m} ((), k_{0} s_{1} ρ)

) and quasi‐electrostat...…”

Section: Analytical Descriptionmentioning

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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z ≳ 25

km.…”

Section: Numerical Simulations' Resultsmentioning

confidence: 99%

“…Note that only the extraordinary (whistler) wave propagates in the frequency band , while the ordinary wave is evanescent. The dispersion law of monochromatic (

\propto \exp ((), 2 π i f t)

) whistlers can be written as follows (Kondrat'ev et al, ):

p^{2} = ε - \frac{1}{2} ((), 1 + \frac{ε}{η}) q^{2} + {([], \frac{1}{4} ((), 1 - \frac{ε}{η}) q^{4} - \frac{g^{2}}{η} q^{2} + g^{2})}^{\frac{1}{2}},

\overset{ε}{true} = ((), \begin{matrix} center center center \\ array ε & array - i g & array 0 \\ array i g & array ε & array 0 \\ array 0 & array 0 & array η \end{matrix}) .

…”

Section: General Properties Of Whistler Wavesmentioning

confidence: 99%

Section: General Properties Of Whistler Wavesmentioning

confidence: 99%

\begin{matrix} alignleft \\ align-1 \{\begin{array}{c} E_{z, m} \\ B_{z, m} \end{array}\} & align-2 = - \exp [- i (m ϕ \pm k_{0} p z)] \sum_{α = 1}^{2} \{\begin{array}{c} i n_{α}^{'} false/ V^{'} \\ c^{- 1} \end{array}\} A_{α} q_{α}^{'} J_{m} (k_{0} q_{α}^{'} ρ), if ρ < a, \\ align-1 \{\begin{array}{c} E_{z, m} \\ B_{z, m} \end{array}\} & align-2 = \exp [- i (m ϕ \pm k_{0} p z)] \sum_{α = 1}^{2} \{\begin{array}{c} i n_{α} false/ V_{0} \\ c^{- 1} \end{array}\} C_{α} s_{α} K_{m} (k_{0} s_{α} ρ), if ρ > a, \end{matrix}

\propto K_{m} ((), k_{0} s_{1} ρ)

) and quasi‐electrostat...…”

Section: Analytical Descriptionmentioning

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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show abstract

“…В случае нерезонансного метаматериала, когда выполняется соотношение sgn µ ⊥ = sgn µ , поверхности показателей преломления распространяющихся нормальных волн являются замкнутыми. Заметим, что аналогичное поведение имеет место и для нормальных волн замагниченной плазмы в зависимости от знаков диагональных компонент тензора ее диэлектрической проницаемости (см., например, [5]).…”

Section: постановка задачи и основные соотношенияunclassified

Теория Ленточной Антенны, Расположенной На Плоской Границе Раздела Одноосного Магнитного Метаматериала И Изотропной Среды

Заборонкова¹,

Зайцева²,

Кудрин³

et al. 2019

Журнал Технической Физики

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A study is made of the electrodynamic characteristics of an antenna having the form of an infinitesimally thin, perfectly conducting narrow strip located at the plane interface of a uniaxial magnetic metamaterial and an isotropic magnetodielectric medium. The antenna is perpendicular to the anisotropy axis of the metamaterial and is excited by a time-harmonic given voltage. Singular integral equations for the antenna current are obtained in the case of an infinitely long strip conductor. Based on the solution of these equations, the current distribution and input impedance of the antenna are found and analyzed. The limits of applicability of an approximate method based on the transmission line theory for determining the antenna characteristics are established. Within the framework of this method, the results obtained are generalized to the case of a finite-length strip antenna.

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Observations and Modeling of Whistler Mode Waves in the Magnetospheric Density Ducts

Streltsov

Bengtson

2020

JGR Space Physics

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This paper presents results from a modeling study of localized packages of very low frequency (VLF) whistler mode waves observed by the NASA Van Allen Probes (also known as the Radiation Belt Storm Probes [RBSP]) satellites in the equatorial magnetosphere. The waves are detected inside enhancements of the plasma density, which we interpret as high-density ducts. The quality of the ducting depends on the wave and duct parameters. The goal of this study is to investigate relations between these parameters. This study is based on the analysis and simulations of the electron MHD model. The results demonstrate that (1) the high-density ducts with the magnitudes and perpendicular sizes observed by the RBSP satellites can trap VLF waves with the observed frequency and guide them over a significant distance with little attenuation. (2) It is possible to identify the range of magnitudes of the parallel and perpendicular wavelengths using the information about frequency of the waves and parameters of the duct.

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Electrodynamics of Density Ducts in Magnetized Plasmas

Cited by 24 publications

References 0 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

Теория Ленточной Антенны, Расположенной На Плоской Границе Раздела Одноосного Магнитного Метаматериала И Изотропной Среды

Observations and Modeling of Whistler Mode Waves in the Magnetospheric Density Ducts

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