Impedance and large signal excitation of satellite-borne antennas in the ionosphere

Baker, Dennis J.; Weil, Herschel; Bearce, L. S.

doi:10.1109/tap.1973.1140550

Cited by 5 publications

(6 citation statements)

References 6 publications

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“…This result was contrary to existing nonlinear sheath models which predicted an increasing capacitive reactance as frequency and voltage increase [Shkarofsky, 1972;Baker et al, 1973].…”

Section: Introductioncontrasting

confidence: 94%

Impedance measurements on a VLF multiturn loop antenna in a space plasma simulation chamber

Koons¹,

Dazey²,

Edgar³

1984

Radio Science

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The Space Sciences Laboratory of The Aerospace Corporation is presently defining an experiment to test a loop antenna configuration for a VLF transmitter in the ionosphere. The primary objectives of the experiment are to validate existing models for radiation by a loop antenna and to study the performance of the antenna in the ionospheric plasma. A one‐third scale model of the antenna has been constructed. Impedance measurements have been made on the model in a 5‐m diameter space plasma simulation chamber at NASA Lewis Research Center. The measurements confirm that the reactance of the antenna in an ionospheric plasma is essentially identical to its free space self‐inductance. The effective series resistance of the circuit increases with frequency. The losses are attributed to power transferred to plasma turbulence.

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“…This result was contrary to existing nonlinear sheath models which predicted an increasing capacitive reactance as frequency and voltage increase [Shkarofsky, 1972;Baker et al, 1973].…”

Section: Introductioncontrasting

confidence: 94%

Impedance measurements on a VLF multiturn loop antenna in a space plasma simulation chamber

Koons¹,

Dazey²,

Edgar³

1984

Radio Science

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“…Therefore, analytical sheath derivations that utilize this Boltzmann factor for voltages in excess of the plasma potential for anything other than DC applied potentials in a collisionless plasma are questionable. On the other hand, collisions such as those present in a dense ionospheric plasma, could certainly aid in speeding up the relaxation of the distribution function back to a Maxwellian state over time scales comparable to or less than the period corresponding to VLF frequencies [ Mlodnosky and Garriott , 1963; Baker et al , 1973].…”

Section: Resultsmentioning

confidence: 99%

“… Shkarofsky [1972] extended the analysis of Mlodnosky and Garriott [1963] to include large signal excitation and the effects of an induced electromotive force (emf) resulting from the drift motion of the antenna at orbit speed (i.e., due to v × B 0 ). The following year Baker et al [1973], using the same linear theory, incorporated a DC bias into their model resulting from spacecraft charging between the antenna and the satellite body on which the antenna was mounted. Mlodnosky and Garriott [1963], Shkarofsky [1972], and Baker et al [1973] all used very crude first order approximations of the current and voltage on the antenna and greatly simplified the description of the sheath region through approximations such as uniform charge density and a simple exponential voltage dependence through the sheath.…”

Section: Introductionmentioning

confidence: 99%

“…The following year Baker et al [1973], using the same linear theory, incorporated a DC bias into their model resulting from spacecraft charging between the antenna and the satellite body on which the antenna was mounted. Mlodnosky and Garriott [1963], Shkarofsky [1972], and Baker et al [1973] all used very crude first order approximations of the current and voltage on the antenna and greatly simplified the description of the sheath region through approximations such as uniform charge density and a simple exponential voltage dependence through the sheath. More recently, Song et al [2007] used a theoretical formulation based upon that of Shkarofsky [1972] to analytically determine the terminal properties and sheath characteristics surrounding electrically short dipole antennas in the inner magnetosphere at large drive voltages relative to the ambient plasma potential.…”

Section: Introductionmentioning

confidence: 99%

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Fluid simulation of the collisionless plasma sheath surrounding an electric dipole antenna in the inner magnetosphere

2010

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[1] The electrostatic sheath formation surrounding an electric dipole antenna at very low frequencies (VLF) in a magnetoplasma is examined through numerical simulation. In this paper, a hydrodynamic approach is used to solve for the nonlinear sheath dynamics of antennas located in plasmas similar to that which exists in the plasmasphere between L = 2 and L = 3 in the geomagnetic equatorial plane. The plasma environment at this location is assumed to be fully ionized and collisionless consisting of electrons and protons. Poisson's equation is used to close the system, providing the quasi-electrostatic fields within the sheath region. Sheath characteristics are given as a function of antenna drive frequency and voltage with results that are compared with existing theory. Capacitance and resistance values are given to reflect the sheath's contribution to the input impedance of the antenna. Finally, the importance of ion motion and the nonlinear sheath effects on the current, charge collection and bias voltage for the transmitting antenna are shown. The primary assumptions underlying the closure mechanisms for the infinite set of fluid moments are examined through theoretical observations and simulated comparisons of the truncation schemes. This paper constitutes one of the first works on the subject of high-voltage transmitting dipole antenna in a space plasma using a three-dimensional nonlinear formulation.Citation: Chevalier, T. W., U. S. Inan, and T. F. Bell (2010), Fluid simulation of the collisionless plasma sheath surrounding an electric dipole antenna in the inner magnetosphere, Radio Sci., 45, RS1010,

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“…A number of early works have included the plasma sheath effects in investigations of the antenna impedance [e.g., Mlodnosky and Garriott , 1963; Shkarofsky , 1972; Baker et al , 1973]. However, the physics of the antenna–plasma interaction, particularly in the case of the high‐voltage antennas, has not been well understood.…”

Section: Introductionmentioning

confidence: 99%

Plasma sheath structures around a radio frequency antenna

Song

Reinisch

2008

J. Geophys. Res.

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A one‐dimensional particle‐in‐cell (PIC) simulation code is developed to investigate plasma sheath structures around a high‐voltage transmitting antenna in the inner magnetosphere. We consider an electrically short dipole antenna assumed to be bare and perfectly conducting. The oscillation frequency of the antenna current is chosen to be well below the electron plasma frequency but higher than the ion plasma frequency. The magnetic field effects are neglected in the present simulations. Simulations are conducted for the cases without and with ion dynamics. In both cases, there is an initial period, about one‐fourth of an oscillation cycle, of antenna charging because of attraction of electrons to the antenna and the formation of an ion plasma sheath around the antenna. With the ion dynamics neglected, the antenna is charged completely negatively so that no more electrons in the plasma can reach the antenna after the formation of the sheath. When the ion dynamics are included, the electrons impulsively impinge upon the antenna while the ions reach the antenna in a continuous manner. In such a case, the antenna charge density and electric field have a brief excursion of slightly positive values during which there is an electron sheath. The electron and ion currents collected by the antenna are weak and balance each other over each oscillation cycle. The sheath–plasma boundary is a transition layer with fine structures in electron density, charge density, and electric field distributions. The sheath radius oscillates at the antenna current frequency. The calculated antenna reactance is improved from the theoretical value by 10%, demonstrating the advantage of including the plasma sheath effects self‐consistently using the PIC simulations. The sheath tends to shield the electric field from penetrating into the plasma. There is, however, leakage of an electric field component with significant amplitude into the plasma, implying the applicability of the high‐voltage antennas in whistler wave transmission in the inner magnetosphere.

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Impedance and large signal excitation of satellite-borne antennas in the ionosphere

Cited by 5 publications

References 6 publications

Impedance measurements on a VLF multiturn loop antenna in a space plasma simulation chamber

Impedance measurements on a VLF multiturn loop antenna in a space plasma simulation chamber

Fluid simulation of the collisionless plasma sheath surrounding an electric dipole antenna in the inner magnetosphere

Plasma sheath structures around a radio frequency antenna

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