Radio-frequency impedance probes

Kaiser, Thomas; Tunaley, J. K. E.

doi:10.1007/bf00362570

Cited by 10 publications

(2 citation statements)

References 23 publications

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“…Most theoretical work on VLF antenna radiation in a magnetoplasma has so far been done under the assumption that the plasma is cold , and only a few workers have considered the effects of finite temperature in the antenna radiation characteristics [21][22][23][24][25][26][27]. The bulk of the knowledge on this subject can be found in a number of recent review articles such as [28 or 29].…”

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Electric dipole radiation at vlf in a uniform warm magneto-plasma

Wang

Bell

1972

Rev. Phys. Appl. (Paris)

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Reçu le 20 septembre 1971) Résumé. 2014 Cet article traite des caractéristiques de rayonnement à très basse fréquence d'une antenne dipolaire mince dans un magnétoplasma tiède. Les solutions formelles sont obtenues pour la partie de la résistance de rayonnement due aux modes thermiques (Rt) et au mode sifflement (Rw). Dans ce calcul, les ions sont supposés au repos, et les effets de température non nulle sont introduits au moyen d'un terme de pression scalaire. Deux orientations particulières du dipôle sont prises en considération (orientations parallèle et perpendiculaire à la ligne de force du champ magnétique statique). Une analyse détaillée est effectuée pour les fréquences comprises entre la fréquence gyromagnétique électronique (fHe) et la fréquence de résonance hybride inférieure (fLHR). Plusieurs graphes numériques de Rt~, et Rw~, sont présentés pour des valeurs typiques des paramètres du plasma magnétosphérique aux très basses fréquences. Pour des fréquences (f) éloignées de fLHR, Rt~, est généralement inférieure à 2 x 10-1 Rw~, tandis que pour f ~ fLHR, Rt~, ~ 10-1 R et Rt~ ~ Rw~. Utilisant ces valeurs numériques de Rt~, et Rw~, le rendement du rayonnement dipolairẽ w pour le mode sifflement a été évalué pour un certain nombre de cas particuliers. Dans la plupart des cas, ~w ~ 70 %, mais décroît à ~ 38 % pour f ~ fLHR.

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Electric dipole radiation at vlf in a uniform warm magneto-plasma

Wang

Bell

1972

Rev. Phys. Appl. (Paris)

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“…In most theoretical treatments of this device, the Maxwell displacement current term is openly dropped, therefore assuming the disappearance of the free space electromagnetic mode. Several review works are available that describe attempts to accurately quantify the impedance of the probe‐plasma configuration; we direct the reader particularly to Kaiser and Tunaley [] for a readable yet comprehensive review. Here we give a brief description of the motivation behind the measurement technique, from a fluid dispersion perspective.…”

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Ionosphere plasma electron parameters from radio frequency sweeping impedance probe measurements

Spencer

Patra

2015

Radio Science

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In this work we will describe the technique of using an RF sweeping impedance probe (SIP) to measure the AC impedance of an electrically short monopole immersed in a plasma. We analyze the SIP measurements which are taken from the payload of the Storms sounding rocket, launched from Wallops Island, Virginia, in 2007. The scientific objective of the Storms mission was to concentrate on whether density irregularities observed in midlatitude spread F could arise from ionospheric coupling to terrestrial weather. As such, independent measurements of the electron density profile are crucial. Since the inherent nature of the SIP technique makes it relatively insensitive to errors introduced through spacecraft charging, probe contamination, and other DC effects, it is an ideal instrument to employ under disturbed plasma conditions. The instrument measures both the magnitude and phase of the AC impedance from 100 kHz to 20 MHz in 128 frequency steps, performing 45,776 sweeps over the entire flight. From these measurements we infer both the absolute electron density n e and the electron neutral collision frequencies en throughout the flight trajectory. The SIP data can be approximately analyzed using a fluid formulation and thin sheath approximation particularly at altitudes below 200 km, which allows us to match the measurements to quasi-static analytical formulas. At about 265 km on the upleg, the magnitude data transitioned to a highly damped response with increasing altitude. The phase data, on the other hand, continued to indicate increased plasma density and reduced collisionality as expected. For a large portion of the flight, the payload of the Storms mission exhibited an uncontrolled coning motion, making the local magnetic field orientation with respect to the dipole difficult to decipher. Despite these difficulties, we were able to obtain robust estimates of the electron density profile, using the phase information from each sweep. In addition, the electron neutral collision frequency obtained from matching to phase data alone was on the correct order of magnitude with respect to Naval Research Laboratory Mass Spectrometer Incoherent Scatter-Extended model values in the ionosphere between 100 km and 150 km.

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The Distortion of an Electromagnetic Wave Field by a Cavity in a Cold Magneto-Plasma

Kaiser

Kendall

1973

Astrophysics and Space Science Library

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Radio-frequency impedance probes

Cited by 10 publications

References 23 publications

Electric dipole radiation at vlf in a uniform warm magneto-plasma

Electric dipole radiation at vlf in a uniform warm magneto-plasma

Ionosphere plasma electron parameters from radio frequency sweeping impedance probe measurements

The Distortion of an Electromagnetic Wave Field by a Cavity in a Cold Magneto-Plasma

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