Investigation of a hollow cathode discharge plasma.
SERT 2 mercury vapor fed hollow cathode operated in bell jar, determining volt-ampere characteristics and flow rates for plasma diagnostics
Csiky, G. A.↗
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The fine structure of the earth's collisionless shock wave.
Collision free earth shock wave gross and fine structure deduced from OGO 5 plasma diagnostics
Fredricks, R. W.↗
Langmuir probe measurements in a discharge from a hollow cathode
SERT 2 mercury vapor fed hollow cathode operated in bell jar, determining volt-ampere characteristics and flow rates for plasma diagnostics
Csiky, G. A.↗
Comparison of theoretical and flight-measured ionization in a blunt body reentry flow field
Plasma diagnostic data from onboard Langmuir probes, reflectometers, antenna VSWR and beacon and telemetry attenuation for blunt body reentry flow field
Evans, J. S.↗
Flight results of a 25000-foot-per-second reentry experiment using microwave reflectometers to measure plasma electron density and standoff distance
Comparing results of reentry plasma diagnostic experiment at 25,000 ft/sec with flow-field values at four locations on spacecraft
Grantham, W. L.↗
Reentry plasma measurements using a four frequency reflectometer
Hypersonic reentry plasma diagnostic measurements made with four-frequency microwave reflectometer
William L. Grantham↗
Evaluation of an abnormal-glow discharge for use as a laboratory plasma source
Abnormal glow discharge from cathode configuration for use as laboratory test bed to develop and calibrate plasma diagnostic sensors
Grantham, W. L.↗
Electrostatic-probe measurements of plasma parameters for two reentry flight experiments at 25000 feet per second
Unique plasma diagnostic measurements at high altitudes from two geometrically similar blunt body reentry spacecraft using electrostatic probe rakes are presented. The probes measured the positive ion density profiles (shape and magnitude) during the two flights. The probe measurements were made at eight discrete points (1 cm to 7 cm) from the vehicle surface in the aft flow field of the spacecraft over the altitude range of 85.3 to 53.3 km (280,000 to 175,000 ft) with measured densities of 10 to the 8th power to 10 to the 12th power electrons/cu cm, respectively. Maximum reentry velocity for each spacecraft was approximately 7620 meters/second (25,000 ft/sec). In the first flight experiment, water was periodically injected into a flow field which was contaminated by ablation products from the spacecraft nose region. The nonablative nose of the second spacecraft thereby minimized flow field contamination. Comparisons of the probe measured density profiles with theoretical calculations are presented with discussion as to the probable cause of significant disagreement. Also discussed are the correlation of probe measurements with vehicle angle of attack motions and the good high altitude agreement between electron densities inferred from the probe measurements, VHF antenna measurements, and microwave reflectometer diagnostic measurements.
Jones, W. L., Jr.↗
The particles and fields subsatellite magnetometer experiment
It is reported that the objectives of the particles and fields subsatellite (PFS) magnetometer experiment are to calculate the interior electrical conductivity of the moon, to survey the remanent magnetization of the lunar surface, and to study the interaction of the moon with its plasma environment. The magnetometers also support the PFS particle experiment by providing onboard magnetic sectoring and a posteriori pitch angle data and plasma diagnostics.
Coleman, P. J., Jr.↗
Wavelength-selective, sequential Q-switching laser cavity
Single-frequency continuous output of laser is converted into series of high-power laser pulses at high repetition rates. Applications include pollutant detection by absorption, laser gain measurements at discrete wavelengths, laser propagation measurement, and laser plasma diagnostics.
Allario, F.↗
Measurement of plasma temperature and density using laser absorption
A laser radiation absorption technique, suitable for temporal measurement of the electron density, the temperature, or a simultaneous determination of both, in an LTE plasma, is discussed. The theoretical calculation of the absorption coefficient for a hydrogen plasma is outlined; some results are presented for visible wavelengths. Measurements of electron density and temperature are presented and shown to be in good agreement with those values obtained by other methods. Finally, the possible use of the argon ion laser for simultaneous electron density and temperature measurement is discussed, and the theoretical curves necessary for its application to hydrogen plasma diagnostics are shown.
Billman, K. W.↗
Structure of the ionospheric disturbances about planetary entry probes
Local ionospheric disturbances which would be created by a planetary entry probe are investigated. Competing theories of spacecraft-ambient plasma interactions are used to estimate computationally the perturbations of the plasma, particularly the structure of the near wake behind planetary entry vehicles. The results have bearing on the location and operation of plasma diagnostic instrumentation aboard planetary entry vehicles. Recent estimates of Mars ionospheric properties plus vehicle dimensions and speeds similar to those of the Viking Mars Lander are used to define the parameters essential to the theory. Smaller entry bodies are also considered. Comparisons are made of the results based on the different theories for a given assumed planetary atmosphere, and also with the perturbations a similar vehicle would generate in the earth's ionosphere.
Weil, H.↗
Absorption coefficients of a hydrogen plasma for laser radiation
The formalism for the calculation of the absorption of radiation by a hydrogen plasma at common laboratory conditions is summarized. The hydrogen plasma absorption coefficient for laser radiation has been computed for a wide range of electron densities and temperatures (10,000-40,000 K). The results of this computation are presented in a graphical form that permits a determination of the absorption coefficient for the following laser wavelengths: 0.176, 0.325, 0.337, 0.442, 0.488, 0.515, 0.633, 0.694, 1.06, 1.15, 2.36, 3.39, 5.40 and 10.6 microns. The application of these results and laser radiation absorption measurements to plasma diagnostics is discussed briefly.
Stallcop, J. R.↗
Numerical procedure for analyzing Langmuir probe data
A numerical procedure is proposed for analyzing Langmuir probe data in the presence of a two-group plasma containing both primary and Maxwellian electrons. The procedure is known as a least-squares differential-correction technique for determining the unknown coefficients of the governing equation. It is shown that for a given set of input data the results of the analysis are unique and independent of the initial estimate of electron temperature, that convergence is fastest when electron temperature is overestimated, that the results are sensitive to the region of the curve used as input and also to the voltage increment, and that plasma properties determined by the proposed numerical procedure are either consistent with those determined graphically or closer to expected values. With a suitable data acquisition system, the Fortran IV program worked out for this procedure could be used to provide real-time plasma diagnostic information for an operating ion thruster.
Beattie, J. R.↗
Report on the solar physics-plasma physics workshop
The paper summarizes discussions held between solar physicists and plasma physicists on the interface between solar and plasma physics, with emphasis placed on the question of what laboratory experiments, or computer experiments, could be pursued to test proposed mechanisms involved in solar phenomena. Major areas discussed include nonthermal plasma on the sun, spectroscopic data needed in solar plasma diagnostics, types of magnetic field structures in the sun's atmosphere, the possibility of MHD phenomena involved in solar eruptive phenomena, the role of non-MHD instabilities in energy release in solar flares, particle acceleration in solar flares, shock waves in the sun's atmosphere, and mechanisms of radio emission from the sun.
Sturrock, P. A.↗
Common-cavity pumped laser
Two lasers linked by dichroic coupler are packaged in single cavity. Resulting system is more compact, efficient, and durable than conventional two-cavity lasers. Such instruments (portable pumped lasers) are needed for spectroscopy in plasma diagnostics in atmospheric research, and in radar-like devices for seeing through dense fog or smoke.
Koepf, G. A.↗
Spacecraft charging control by thermal, field emission with lanthanum-hexaboride emitters
Thermal, field emitters of lanthanum (or perhaps cerium) hexaboride (LaB6) with temperature variability up to about 1500K are suggested for spacecraft charging control. Such emitters operate at much lower voltages with considerably more control and add plasma-diagnostic versatility. These gains should outweigh the additional complexity of providing heat for the LaB6 thermal, field emitter.
Morris, J. F.↗
Plaid evaluation of visual access for PDP berthing and deployment
Tests were performed to evaluate visual access for berthing and deployment of the Plasma Diagnostic Package (PDP) in Space Transportation 4 Flight (STS-4). The Panel Layout Automated Interactive Design (PLAID), a 3 D computer graphics package, was used to construct models of the PDP, pallet, orbiter payload bay, the Remote Manipulator System (RMS), and other relevant elements to represent the STS-4 configuration. Several different assemblies were made, each one representing a snapshot of the PDP during berth/deploy maneuvers. Thirty-six views were produced during this test.
Brown, J. W.↗