On VLF Radiation Resistance of an Electric Dipole in a Cold Magnetoplasma

Wang, T. N. C.; Bell, T. F.

doi:10.1029/rs005i003p00605

Cited by 36 publications

(41 citation statements)

References 2 publications

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“… Kulkarni et al [2006] expanded on the results presented in Inan et al [2003] to determine source locations in L ‐shell and geomagnetic latitude, operating frequencies and initial wave normal angles needed to fill the inner radiation belts with whistler‐mode wave energy. The authors used the Stanford VLF raytracing code [ Inan and Bell , 1977], coupled with path‐integrated Landau damping and a realistic model [ Wang and Bell , 1970] of dipole antenna radiation in a magnetoplasma. Kulkarni et al [2006] considered both equatorial and off‐equatorial source locations, and concluded that three transmitters radiating in accordance with the Wang and Bell [1970] antenna model are sufficient to fill the inner magnetosphere with whistler‐mode wave energy, although the authors ignored longitudinal spreading of the rays.…”

Section: Introductionmentioning

confidence: 99%

“…The authors used the Stanford VLF raytracing code [ Inan and Bell , 1977], coupled with path‐integrated Landau damping and a realistic model [ Wang and Bell , 1970] of dipole antenna radiation in a magnetoplasma. Kulkarni et al [2006] considered both equatorial and off‐equatorial source locations, and concluded that three transmitters radiating in accordance with the Wang and Bell [1970] antenna model are sufficient to fill the inner magnetosphere with whistler‐mode wave energy, although the authors ignored longitudinal spreading of the rays.…”

Section: Introductionmentioning

confidence: 99%

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Energetic electron precipitation induced by space based VLF transmitters

2008

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[1] Numerical raytracing with Landau damping is used to calculate electron precipitation that would be induced by in situ sources located at L = 2 and L = 2.5, at the geomagnetic equator and also at a geomagnetic latitude of 20°along each field line. In accordance with the Wang and Bell (1970) model of antenna radiation in a magnetoplasma, we consider frequencies immediately below, approximately equal to, and 1 kHz above the local lower hybrid resonance frequency at each location and injected rays within 3°of the resonance cone. The magnetospherically reflecting (MR) whistler-mode waves that are injected from such in situ sources propagate with a wave normal angle very close to the resonance cone. Compared to a single-pass interaction, such MR waves precipitate up to 16 times more 100 keV to 5 MeV electrons. Waves injected at initial wave normal angles closer to the magnetic field, e.g., 45°, in fact precipitate fewer >1 MeV electrons than waves injected close to the resonance cone.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Energetic electron precipitation induced by space based VLF transmitters

2008

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“…This slow decay rate distinguishes the generation of the whistler waves by magnetic dipole and the RMF source antennas from the generation of whistler waves by an electric dipole antenna, which has been studied by many authors theoretically, experimentally, and numerically. [12][13][14][15][16][17][18] In Ref. 14 it is clearly demonstrated that in the case of linear small magnitude whistler waves driven by the electric dipole antenna the magnitude of the wave decays very fast along the ambient magnetic field even in the collisionless plasma due to the fact that the energy radiated is nearly evenly distributed inside the resonance cone.…”

Section: Comparison Of Emhd Model and Experimentsmentioning

confidence: 99%

Generation of whistler waves by a rotating magnetic field source

Karavaev¹,

Gumerov²,

Papadopoulos³

et al. 2010

Physics of Plasmas

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The paper discusses the generation of polarized whistler waves radiated from a rotating magnetic field source created via a novel phased orthogonal two loop antenna. The results of linear three-dimensional electron magnetohydrodynamics simulations along with experiments on the generation whistler waves by the rotating magnetic field source performed in the large plasma device are presented. Comparison of the experimental results with the simulations and linear wave properties shows good agreement. The whistler wave dispersion relation with nonzero transverse wave number and the wave structure generated by the rotating magnetic field source are also discussed. The phase velocity of the whistler waves was found to be in good agreement with the theoretical dispersion relation. The exponential decay rate of the whistler wave propagating along the ambient magnetic field is determined by Coulomb collisions. In collisionless case the rotating magnetic field source was found to be a very efficient radiation source for transferring energy along the ambient magnetic field lines.

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“…Previous authors have characterized the radiation reactance in the far-field region of an electric dipole immersed in a magnetoplasma and in the absence of a plasma sheath [3], [16], [17], [18]. More specifically, Balmain [3] develops a quasi-static approximation of the far-field radiation resistance that is valid for any orientation of the electric dipole with respect to the magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Radiation pattern of a ULF space-based antenna for controlled removal of energetic trapped protons

Soria-Santacruz

Martı́nez-Sánchez

Chen

et al. 2015

2015 IEEE Aerospace Conference

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Highly energetic protons trapped in the inner Van Allen belt can disturb spacecraft operations, contaminate scientific measurements, and even cause early termination of missions. Earlier papers proposed that space-based coil antennas in the Electromagnetic Ion Cyclotron (EMIC) wave regime could potentially remove these particles by precipitating them into the atmosphere. Specifically, the designs involve a coil antenna driven in DC but rotating at the desired EMIC frequency (that is, below the proton gyrofrequency), which is capable of generating these waves and could serve as a payload on a scientific mission with the purpose of testing the ideas behind the concept of controlled removal of energetic trapped protons. This paper focuses on the radiation characteristics of this potential payload. We calculate the radiation pattern and radiation resistance of this transmitter operating in the EMIC band, taking into account the response of the plasma. We present a full-wave linear model capable of calculating the radiation pattern and radiation resistance in the far-field region of the rotating coil configuration immersed in a cold magnetized plasma consisting of protons and electrons. The stationary phase method is used to find a solution to the inverse Fourier transform of the radiated fields. The model shows that the power flux is fairly confined within a very small cone around the geomagnetic field lines, which corresponds to the waves' resonance cone; the corresponding wave number vectors, however, are close to perpendicular to the Poynting flux direction. The radiation resistance is at a maximum for coil axis perpendicular to the geomagnetic field lines, which defines a preferred axis of rotation for the coil constituting the transmitter. Additionally, we show that the radiated power increases with increasing rotation frequency. We present at the end of the paper a brief discussion on thermal effects and other assumptions which should be carefully reconsidered in future efforts.

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On VLF Radiation Resistance of an Electric Dipole in a Cold Magnetoplasma

Cited by 36 publications

References 2 publications

Energetic electron precipitation induced by space based VLF transmitters

Energetic electron precipitation induced by space based VLF transmitters

Generation of whistler waves by a rotating magnetic field source

Radiation pattern of a ULF space-based antenna for controlled removal of energetic trapped protons

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