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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Boundary layer separating collisionless plasma from one dimensional magnetic field for anisotropic particle velocity distribution functions, preserving charge neutrality in boundary layer
Synchrotron emission of relativistic particle in magnetic field with radiative reaction force comparable to Lorentz force, emphasizing pulsar cosmic ray electron acceleration
Vector magnetic field and energetic particle flux profiles, indicating geomagnetically aligned currents associated with visible auroral arc
Transverse magnetic disturbances in auroral oval, examining movement, intensity, particle fluxes and field magnitude
Fluid electrophoresis separation based on motion of particles in electric field for demonstrating near-zero-gravity condition in space - Apollo 14
Theoretical work designed to bridge the gap between celestial mechanics and the motion of charged particles in magnetic fields is presented. Attempts are made to devise a simple uninvolved method to solve adiabatic invariant motion problems. The method is illustrated by solving a problem involving the motion of a slowly perturbed harmonic oscillator.
Several spacecraft experimenters have reported on the detection of large temporal variations in trapped electron fluxes near L = 5 to 6 at midlatitudes in the night hemisphere. In this report we describe in detail the particle, wave, and field changes measured when Ogo 5 traversed an outer-zone trapping boundary of this type on September 7, 1968. It is shown that thermal proton concentrations and E greater than 50-keV electron fluxes abruptly decreased when electrons with (1-4) keV mean energy were detected. It is also shown that currents flowed along the average geomagnetic field direction near the plasma boundaries and that these were accompanied by intense VLF electrostatic waves. It is proposed that turbulent resistivity produced by current-driven plasma instabilities allows parallel dc electric fields to develop along this boundary.
The differential energy spectra of cosmic-ray positrons and negatrons with energies between approximately 11 and 1500 MeV was measured during the period 1968-1971 using a balloon-borne magnetic spectrometer. These measurements fill a gap in the previously existing data and permit the determination of the interstellar spectra of cosmic-ray positrons and electrons. Knowledge of these spectra provides a crucial tool for studies of the distribution and density of matter and magnetic fields in the interstellar medium and the origin and dynamics of energetic particles contained in the fields. The differential energy spectrum of interstellar electrons may be represented as a power-law, j alpha T to the -1.8 power for 100 MeV approximately T approximately 2 GeV, but must flatten considerably at lower energies. From the measured electron charge composition, it is concluded that the majority of cosmic-ray electrons with energies above approximately 10 MeV originate in primary sources.
Physical phenomena associated with the interaction between auroral particles and electromagnetic fields, auroral energy flow, and the propagation of auroral effects to low altitudes are discussed in detail. It is concluded that energy deposition of soft auroral X-rays would be negligible at stratospheric altitudes. New data from incoherent backscatter measurements of neutral winds in the auroral region indicate a lack of correlation between stratospheric winds and winds in the auroral ionosphere. Magnetograms are used to show that sector boundary crossings with a time scale of approximately one hour (as opposed to the sector structure itself with a time scale of several days) do not couple effectively with the magnetosphere and are not significant energy inputs to it.
An X-ray observation of the Norma-Lupus region, charge and isotope measurements of heavy cosmic ray nuclei and their role in the determination of cosmic ray age, and the possibility of a contribution to primary cosmic ray spectra from pulsars are among the topics covered in papers concerned with some of the results of recent cosmic ray research. Other topics covered include multiple scattering of charged particles in magnetic fields, absorption of primary cosmic rays in the atmosphere, and phase lag effects on cosmic ray modulation during a recent solar cycle. Individual items are announced in this issue.
Geoscience instrumentation systems are considered along with questions of geoscience environment, signal processing, data processing, and design problems. Instrument platforms are examined, taking into account ground platforms, airborne platforms, ocean platforms, and space platforms. In situ and laboratory sensors described include acoustic wave sensors, age sensors, atmospheric constituent sensors, biological sensors, cloud particle sensors, electric field sensors, electromagnetic field sensors, precision geodetic sensors, gravity sensors, ground constituent sensors, horizon sensors, humidity sensors, ion and electron sensors, magnetic field sensors, tide sensors, and wind sensors. Remote sensors are discussed, giving attention to sensing techniques, acoustic echo-sounders, gamma ray sensors, optical sensors, radar sensors, and microwave radiometric sensors.
A special orbital radiation study was conducted for the SOLWIND project to evaluate mission-encountered energetic particle fluxes. Magnetic field calculations were performed with a current field model, extrapolated to the tentative spacecraft launch epoch with linear time terms. Orbital flux integrations for circular flight paths were performed with the latest proton and electron environment models, using new improved computational methods. Temporal variations in the ambient electron environment are considered and partially accounted for. Estimates of average energetic solar proton fluences are given for a one year mission duration at selected integral energies ranging from E greater than 10 to E greater than 100 MeV; the predicted annual fluence is found to relate to the period of maximum solar activity during the next solar cycle. The results are presented in graphical and tabular form; they are analyzed, explained, and discussed.
Recommendations for a 1979 Mariner Jupiter-Uranus mission are discussed with the possibility of launching the first outer planet atmospheric entry probe. Measurement categories considered for the mission include conducting imaging experiments, observations in both the IR and UV spectral range, experiments associated with magnetic fields, plasma, charged particles, and S- and X-band occultation measurements.
Radio emissions from the direction of Saturn are analyzed which were observed by IMP-6 at 15 frequencies between 375 and 2200 kHz from April 1971 to October 1972. The radio bursts are identified in the IMP-6 data by a phase analysis of the spin-modulated signal from the spacecraft's dipole antenna, and approximately 12 storms are isolated whose occurrence corresponded to times when the spacecraft had an unobstructed view in the direction of Saturn. The spectral character of the radiation is found to be analogous to that of Jupiter, and a power-spectral analysis of the storm occurrence times indicates a weak periodicity for some of the observing frequencies. The Saturnian emission most similar to Jupiter's decametric emission is found to be strongest at 1100 kHz with a bandwidth of about 1000 kHz. A secondary spectral peak may exist at 400 kHz, which is similar to that observed for Earth and Jupiter. The detection of this nonthermal radio emission is shown to be the first direct evidence for the existence of a Saturnian magnetic field containing energetic particles.
A one-component, fringe type laser velocimeter in the backscatter mode was used to measure flow velocities from 732 to 792 m/sec about a shock from an inclined flat plate in a Mach 5 tunnel. This test was chosen to determine system characteristics in applying the laser velocimeter to measure velocities in hypersonic flow fields. The seeding particles, less than 20 microns in diameter, were injected into the tunnel supply pipe, approximately 1 meter upstream of the nozzle throat, through a rake along the diameter. The LV signals were processed by two methods, a scanning spectrum analyzer and a high-speed counter. The measured velocity distributions obtained were analyzed to determine the errors due to particle lag, transit time broadening and high-speed counter quantizing error.
A review and analysis are presented of data derived from the Pioneer 10 and Pioneer 11 flybys of Jupiter on the Jovian plasma, magnetic field, and energetic particles in circumjovian space. The design of the space probes is described along with the principal experiments flown. Overall features of the Jovian magnetosphere are drawn and contrasted with the earth's magnetosphere. The trajectories of the two space probes are contrasted and their data on Jupiter's plasmasphere are correlated. Isointensity contours and count rates of energetic particles are plotted, flux tubes within the Jovian magnetosphere are mapped, the ring current (plasma torus) encircling the planet is described, and possible effects of solar wind and of the moons immersed in Jupiter's magnetosphere are considered.
The influence of the sector structure on the fundamental quantities (densities, temperatures, pressure, composition, electric and magnetic fields, etc.) in the magnetosphere, ionosphere and atmosphere is discussed, and daily synoptic observations of these quantities are recommended for future sun-weather investigations. Extended Shuttle missions are proposed to carry out these observations. Continuous observations of the interplanetary quantities such as the solar wind velocity, density, temperature and composition, the vector interplanetary magnetic field, and energetic particle fluxes through a wide range of energies are also recommended for understanding the extraterrestrial causes of terrestrial effects. The Heliocentric Spacecraft of the International Sun-Earth Explorer Project which remains 0.01 astronomical units from the earth is found to be the best means of carrying out these interplanetary observations.
A study is made of electrons in the drift and bounce loss cones of the magnetospheric slot region. It is observed that discrete events account for the arrival of most electrons in the 100-400 keV range into the drift loss cone. Most such events originate from a high power level VLF transmitter. Calculations of the loss rate caused by the events indicate that the electron flux in the slot region may decrease by as much as 50% per day. It is likely that wave-particle interaction occurs low on the field line due to the particular particle energies and wave frequencies. In order to transport particles to the lower interaction region, additional near-equator scattering, via power-line harmonic emissions or ELF hiss, may be required.