Development of a high-time/spatial resolution self-impedance probe for measurements in laboratory and space plasmas
Autor: | Erik Tejero, Ami DuBois, William E. Amatucci, George Gatling |
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Rok vydání: | 2021 |
Předmět: |
010302 applied physics
Physics business.industry Plasma parameters Resolution (electron density) Plasma oscillation 01 natural sciences 010305 fluids & plasmas law.invention Optics law Monopulse radar 0103 physical sciences Dipole antenna Center frequency business Instrumentation Electrical impedance Image resolution |
Zdroj: | Review of Scientific Instruments. 92:015118 |
ISSN: | 1089-7623 0034-6748 |
Popis: | Plasma impedance probes are often used in laboratory experiments as well as in space to make measurements of important plasma parameters such as the electron density. Conventional impedance probe methods involve sweeping the frequency applied to the probe through a range containing the plasma frequency, which can take on the order of a second to complete. This acquisition time leads to very low spatial resolution when making measurements from sounding rockets in the ionosphere. A high-time resolution impedance probe is under development at the U.S. Naval Research Laboratory with the goal of increasing the spatial resolution of measurements in space. To achieve this, a short-time Gaussian monopulse with a center frequency of 40 MHz and containing a full spectrum of frequencies is applied to an electrically short dipole antenna. Laboratory experiments were performed with the Gaussian monopulse triggered once every 10 µs and averaged over ten shots, equating to a spatial resolution of 13 cm for a typical sounding rocket speed. This paper discusses the development of the new high-time/spatial resolution self-impedance probe and illustrates that the short-time pulse method yields results that match well with data taken using conventional methods. It is shown that plasma parameters such as the electron density, sheath frequency, and electron-neutral collision frequency can also be derived from the data. In addition, data from the high-time/spatial resolution impedance probe are shown to compare well with those from theoretical impedance models. |
Databáze: | OpenAIRE |
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