Measurement of ionospheric electron densities using an RF probe technique

Jackson, John E.; Kane, Julius

doi:10.1029/jz064i008p01074

Cited by 50 publications

(12 citation statements)

References 3 publications

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“…3 More recently in the laboratory there have been continuing experimental and theoretical studies 4,5 of plasma-sheath resonance phenomena. In addition to providing electron density, recent work 4 concentrates on improving low pressure plasma processing by providing a novel operation mode for parallel plate rf plasma reactors.…”

Section: Introductionmentioning

confidence: 99%

On collisionless energy absorption in plasmas: Theory and experiment in spherical geometry

et al. 2006

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An investigation of the rf impedance characteristics of a small spherical probe immersed in a laboratory plasma is ongoing in the large Space Physics Simulation Chamber [D. N. Walker et al., Rev. Sci. Instrum. 65, 661 (1994)] at the Naval Research Laboratory. The data taken are from network analyzer measurements of the reflection coefficient obtained when applying a low level rf signal to the probe which is either near floating potential or negatively dc biased in a low pressure plasma. As is well known, sheaths form around objects placed inside plasmas. The electron density is smaller inside the sheath, and the reduction in density alters the plasma impedance. Surprisingly, the impedance becomes “resistive,” even though the plasma is effectively collisionless, at frequencies below the bulk plasma frequency, thus leading to collisionless energy absorption. This behavior comes directly from Maxwell's equations along with the cold fluid equations. The solutions obtained indicate that this form of plasma resistance is inversely proportional to the plasma density gradient evaluated at the location where the plasma frequency is equal to the applied frequency. The sphere for this work is typically near plasma potential or biased more negatively into the ion collection regime. Applying a supplemental, negative dc bias to the sphere thickens the sheath and tends to raise its resistance as the density gradient is softened. Much of the earlier work in the area of collisionless resistance concentrated primarily on planar probes as opposed to the present work which is concerned with spheres. Interpreting the results is simpler for a sphere and the results obtained agree well with theory as described. For comparison to the theory we use only the S11 parameter outputs (or reflection coefficients) of the network analyzer in the experimental series. Significant energy absorption is observed at frequencies generally near one-half the plasma frequency. One result of this work is that the most efficient transfer of power to the plasma occurs not unexpectedly when there is impedance matching between input impedance and output (collisionless) impedance. This paper is an exposition of these ideas along with data results and a comparison to theory for the spherical probe which has not been published in this form.

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Section: Introductionmentioning

confidence: 99%

On collisionless energy absorption in plasmas: Theory and experiment in spherical geometry

et al. 2006

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“…probe The RF impedance probe observation started before 1960's as described in Jackson and Kane (1959). After that, in 1960's, practical application of the RF impedance probe was realized by Oya (1966) who was inspired by the calculation of probe impedance in plasma by Balmain (1964).…”

Section: Development and Improvement Of Impedancementioning

confidence: 99%

Impedance probe technique to detect the absolute number density of electrons on-board spacecraft

Wakabayashi¹,

Suzuki²,

Uemoto³

et al. 2013

An Introduction to Space Instrumentation

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This text focuses on the impedance probe which is powerful method for observation of absolute electron density in plasma. In several countries, impedance probe has been used during many rocket campaigns and satellite missions by many scientists' groups. In Japan, Oya (1966) realized remarkably accurate electron density observation on-board sounding rocket. Since then, the impedance probe has taken part in absolute electron density measurement to proceed ionospheric and space plasma science in Japan. This text aims to describe impedance probe method which is developed by Oya (1966) as excellent example of in-situ observation of absolute electron density. The following description will provide the historical background, basic theory, advantages, important reminders and specific application ideas of sounding rocket observations during SEEK-2, DELTA and WIND campaigns. This text will refrain from commenting a lot about impedance probe instruments on-board satellites because the authors don't have many experiences with carrying out satellite missions. However, description in this issue will provide some information for future application of satellite experiment. It is expected that engineers, scientists and graduate students who attempt to carry out such impedance probe observation will find effective skills of the method through the text.

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“…Jackson and Kane (1959) first suggested using the RF Impedance Probe to measure characteristics of the ionospheric plasma from spacecraft, and it has seen much use in this application. Jackson and Kane (1959) first suggested using the RF Impedance Probe to measure characteristics of the ionospheric plasma from spacecraft, and it has seen much use in this application.…”

Section: Ionospheric In Situ Measurementsmentioning

confidence: 99%