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Microstrip Plasma Probe

Author : Nicholas V. Karas

Publisher :

Page : 60 pages

File Size : 31,1 MB

Release : 1972

Category : Electric conductivity

ISBN :

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Book Description

The report describes a new diagnostic tool-the microstrip plasma probe-which can be used in the laboratory or in a flight payload with little modification. It is rugged in construction, simple in geometric shape, small in frequency operation and low in power requirements. Since the probe is flush mounted and nonradiating, its analytic capability depends on the modification of its electric fringing fields by the outside medium. A measure of standard parameters--that is, reflection coefficient and insertion loss of the probe-can be related back through a series of equations to the parameters of the disturbing medium. Two general models are presented; one with a lossless center conductor, and one with a lossy center conductor. Where possible, theory and experiment are compared. The results are close. A calibration procedure for both models is described. (Author).



Laboratory and Flight Results of the Microstrip Plasma Probe

Author : Nicholas V. Karas

Publisher :

Page : 62 pages

File Size : 26,8 MB

Release : 1974

Category : Electron distribution

ISBN :

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Book Description

The microstrip plasma probe, a new diagnostic tool for use in the investigation of ionized media, has been developed and successfully tested both in the laboratory and in an actual flight. It is flush mounted (therefore causes no aerodynamic disturbances); simple in geometric shape (therefore can be modified to fit curved surfaces and ruggedized to withstand shock and vibration); only a fraction of the operating wavelength in length (therefore saves on payload space); and operates with low power (therefore does not disturb the plasma which it is measuring). Experimental results, obtained from both the laboratory and from an actual flight, have been compared to theory and to experimental data from other probes. In both instances the results are close.



Bibliography, with Abstracts, of AFCRL Publications from 1 July to 30 September 1972

Author : Air Force Cambridge Research Laboratories (U.S.)

Publisher :

Page : 212 pages

File Size : 29,70 MB

Release : 1972

Category : Geophysics

ISBN :

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Book Description

This bibliography lists all AFCRL in-house reports, journal articles, and contractor reports issued during the reporting period. The DD Form 1473 (Document Control Data - R & D) for each publication is included. In Part I, the 1473's for in-house reports are arranged numerically by the series in which they were issued: in Part II, the 1473's for journal articles are arranged alphabetically by author; in Part III, the 1473's for contractor reports are arranged alphabetically by corporate author. For cross-reference purposes, an index is included, listing the publications numerically by the AFCRL document number.



Performance of a Microwave Antenna System in the Shoulder Region of a Blunt Reentry Nose Cone

Author : J. Leon Poirier

Publisher :

Page : 46 pages

File Size : 19,78 MB

Release : 1973

Category : Microwave antennas

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Book Description

The purpose of the third AFCRL Trailblazer II reentry vehicle flight was to study the effects of shock ionized air on the performance of a microwave antenna system located in the expansion region of the nose cone. The system consisted of a pair of cavity-backed circumferential slot antennas mounted one behind the other on the conical afterbody of the reentry vehicle. During reentry, measurements of antenna impedance mismatch, interantenna coupling, signal attenuation and antenna pattern distortion were made. The data have been compared with computed values and found to be in good agreement. This experiment thus establishes the validity of the various microwave and flow field models and calculations used to obtain the theoretical values in the shoulder region of the reentry body. These results will now serve as a standard against which to compare the properties of various chemical alleviants which are being studied in other flights. (Author).







Interpretation of Microwave Antenna Results from a Reentry Flight Test

Author : John F. Lennon

Publisher :

Page : 58 pages

File Size : 16,52 MB

Release : 1974

Category : Breakdown (Electricity)

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Book Description

This is one of a series of reports on the Trailblazer II program. The particular aspect treated here involves the unmodified expansion-region plasma and its effect on an antenna located on the vehicle shoulder. This report describes some of the theoretical approaches used, discusses the levels of approximation involved, and shows the agreement between these various methods and the test data. The failure of a single set of assumptions to yield consistent agreement over a range of altitudes confirms the need to adopt flow models appropriate to the changing regimes encountered during reentry. One significant conclusion is that performance characteristics such as reflection and interantenna coupling which depend mostly on the level of peak electron density can be represented by simple plane wave, as well as by the more sophisticated slot antenna models. The latter approach, however, is necessary to describe propagation across the entire plasma sheath.



Report on Research at AFCRL.

Author : Air Force Cambridge Research Laboratories (U.S.)

Publisher :

Page : 336 pages

File Size : 10,71 MB

Release : 1972

Category : Geophysics

ISBN :

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Electroacoustic Probe Results Obtained in an Argon Afterglow Plasma for a Planar Geometry

Author : Nicholas V. Karas

Publisher :

Page : 60 pages

File Size : 47,85 MB

Release : 1973

Category : Afterglow (Physics)

ISBN :

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Book Description

Experimental data resulting from an investigation of the electroacoustic probe in an argon afterglow plasma for a planar geometry indicates the value of the probe as a diagnostic tool. It is suited to airborne payloads because of its small size and rugged construction. In carrying out the study, some of the parameters that were varied were the pressure (range = 100 to 1000 micro m), input power to the probe (range = 40 dB), and frequency of input signal (350 to 600 MHz). The effect of changing physical dimensions of the probe was also considered. Electroacoustic probe predictions of the electron density gradients close to a surface were found to compare closely with the electron density gradients obtained with a floating double Langmuir probe. Treating the electroacoustic probe as similar to a resonant circuit produced some preliminary results that show up as familiar Q values. Both linear and nonlinear responses of the electroacoustic probe are illustrated. One nonlinear phenomenon--induced oscillations in sections of the resonance curve--is discussed in detail. (Author).