Antennas in Plasma: Characteristics as Functions of Frequency

Balmain, K. G.

doi:10.1029/rs007i008p00771

Cited by 20 publications

(8 citation statements)

References 35 publications

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“…In addition, Balmain [6] compares his theoretical results with experiment for combinations of neon and argon plasmas obtaining good agreement. Subsequently, Balmain in [7] and [8] provides nice reviews of the relevant literature to date involving the status of antenna research for a variety of plasma environments and antenna types including dipole and loop antennas. These review papers cover such topics as impedance, radiation, resonances, and nonlinearities for both isotropic and anisotropic plasmas.…”

Section: Introductionmentioning

confidence: 99%

Terminal Impedance and Antenna Current Distribution of a VLF Electric Dipole in the Inner Magnetosphere

Chevalier¹,

Inan²,

Bell³

2008

IEEE Trans. Antennas Propagat.

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The current distribution and input impedance of an electric dipole antenna operating in a cold magnetoplasma at very low frequency (VLF) is determined through numerical simulation. A full wave solution of Maxwell's equations using a finite-difference frequency-domain (FDFD) method is implemented to simulate electromagnetic wave propagation in this highly anisotropic medium. The classical perfectly matched-layer (PML) boundary condition is found to exhibit instabilities in the form of nonphysical wave amplification in this environment. To circumvent these difficulties, a PML is developed that is tailored to the cold plasma environment at VLF frequencies. It is shown that the current distribution for antennas with length 100 m is approximately triangular for magnetospheric conditions found at = 2 and = 3 in the geomagnetic equatorial plane. Calculated variations of input impedance as a function of drive frequency are presented for two case studies and compared with predictions of existing analytical work.

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Section: Introductionmentioning

confidence: 99%

Terminal Impedance and Antenna Current Distribution of a VLF Electric Dipole in the Inner Magnetosphere

Chevalier¹,

Inan²,

Bell³

2008

IEEE Trans. Antennas Propagat.

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“…For infinitesimal exciting elements (with spatial Fourier transforms extending to infinity) difficulties were encountered for field and impedance formulations using cold lossless plasmas when the wavevector-surface curvature went to zero particularly as k --> co [Wait, 1968;Balmain, 1972]. After a certain amount of controversy progress was achieved by the realistic approximations of finite antenna size, non- The first work assumed currents in cold plasmas and calculated theoretical radiation patterns.…”

Section: Helliwellmentioning

confidence: 99%

Review of Wave Excitation in Plasmas

Johnston¹

1972

Radio Science

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“…Of particular interest has been the radiation field from an antenna immersed in a cold plasma [e.g., review articles by Ohnuma, 1978;Balmain, 1972;Wait, 1968;andThomas andLandmark, 1969, 1970]. Of particular interest has been the radiation field from an antenna immersed in a cold plasma [e.g., review articles by Ohnuma, 1978;Balmain, 1972;Wait, 1968;andThomas andLandmark, 1969, 1970].…”

Section: Introductionmentioning

confidence: 99%

The excitation of plasma waves by a current source moving in a magnetized plasma: Two‐dimensional propagation

Rasmussen¹,

Banks²,

Harker³

1990

J. Geophys. Res.

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The steady motion of a large conducting body in a magnetized plasma has been shown to create a spatial structure of charges and currents in the plasma which propagate without attenuation along the magnetic field direction (the label “Alfvén wings” has been given to this structure because of its resemblance to the wings of a biplane). In order to show this, it has previously been assumed that the conducting body must be large enough so that frequencies excited in the plasma are significantly below the ion cyclotron frequency Ωi. In this paper, this restriction is relaxed in order to examine the wave pattern emitted at frequencies ω in the entire band, ω < Ωi. It has been found that the Alfvén wing structure breaks up into individual Fourier components which propagate away from the source at an angle slightly greater with respect to the magnetic field than the alignment of the original structure. This process depends on wave frequency. A given frequency is lost from the Alfvén wing structure at a distance which varies as 1/ω³. The amplitude of these traveling waves decreases at a rate which is inversely proportional to the square root of the distance from the source.

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Antennas in Plasma: Characteristics as Functions of Frequency

Cited by 20 publications

References 35 publications

Terminal Impedance and Antenna Current Distribution of a VLF Electric Dipole in the Inner Magnetosphere

Terminal Impedance and Antenna Current Distribution of a VLF Electric Dipole in the Inner Magnetosphere

Review of Wave Excitation in Plasmas

The excitation of plasma waves by a current source moving in a magnetized plasma: Two‐dimensional propagation

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