During the past decade, the plasma frequency probe (PFP) has evolved into an accurate, proven method of measuring electron density in the ionosphere above about 90 km. The instrument uses an electrically short antenna mounted on a sounding rocket that is immersed in the plasma and notes the frequency where the antenna impedance is large and nonreactive. This frequency is closely related to the plasma frequency, which is a direct function of free electron concentration. The probe uses phase-locked loop technology to follow a changing electron density. Several sections of the plasma frequency probe circuitry are unique, especially the voltage-controlled oscillator that uses both an electronically tuned capacitor and inductor to give the wide tuning range needed for electron density measurements. The results from two recent sounding rocket flights (Thunderstorm II and CRIT II) under vastly different plasma conditions demonstrate the capabilities of the PFP and show the importance of in situ electron density measurements of understanding plasma processes.
Measuring ionospheric electron density using the plasma frequency probe
1992-02-01
Miscellaneous
No indication
English
Multiring probe in a flowing ionospheric plasma.
AIAA | 1973
|Estimation of Electron Density of Ionospheric Plasma using Wave, Impedance and Topside Sounder Data
British Library Conference Proceedings | 1997
|Estimation of Electron Density of Ionospheric Plasma using Wave, Impedance and Topside Sounder Data
Online Contents | 1997
|Annex to: Synthesis of ionospheric electron density …
Elsevier | 1988
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