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Chase, L. M.

Publications and source records attributed to Chase, L. M..

13 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Comparison of simultaneous magnetotail and polar ionospheric electric fields and energetic particles

DC electric fields and solar electrons were simultaneously measured by the Apollo 15 subsatellite in the earth's magnetotail at lunar orbital distance and by rocket and balloon experiments in the polar ionosphere. The magnetotail and polar ionosphere transverse electric fields are found generally to agree in magnitude and direction. The electron spectra from 0.5 to 200 keV are essentially identical, indicating that the potential difference due to parallel electric fields between the magnetotail and the rocket located in the polar ionosphere did not exceed approximately 500 V during the time of the measurements.

Mccoy, J. E.↗
NASA NTRS1975

Magnetotail electric fields observed from lunar orbit

Direct observations of convection electric fields in the earth's magnetotail are reported. The electric fields have been measured from lunar orbit by detection of the E x B/B-squared drift displacement of low-energy electrons at the limb of the moon. It is found that electric fields range in magnitude from a value less than or equal to 0.02 mV/m, the limit of sensitivity of the method, to 2 mV/M. The typical value is 0.15 mV/M, and the corresponding convection velocity is 15 km/s. The sense of the electric field is almost always dawn to dusk. The electric field is often variable on a time scale of hours and sometimes minutes. The observations indicate that the electric field is not uniform across the magnetotail. If it is assumed that the typical measured electric-field value represents an average over the inhomogeneities, the potential drop across the entire tail is of the order of 40 kV.

Mccoy, J. E.↗
NASA NTRS1974

Plasma and energetic particles in the magnetotail at 60 earth radii

Particle measurements made by the lunar-orbiting Apollo subsatellites have shown that electron energy spectra in the range 0.55-320 keV in the high-latitude magnetotail often fit a power law with an exponent of -3 and a flux at .5 keV of 200,000 to 700,000 el/sq cm s sr keV. In the magnetosheath, electron energy spectra are similar to the high-latitude magnetotail spectra. In the plasma sheet, electron energy spectra often fit the high-energy tail of a Maxwellian distribution with Eo of about 200-500 eV. During times of substorms a number of cases where the plasma sheet appears to thin at onset have been observed. In addition, cases of plasma sheet expansion at onset have also been observed.

Chase, L. M.↗
NASA NTRS1974

Lunar particle shadows and boundary layer experiment: Plasma and energetic particles on the Apollo 15 and 16 subsatellites

The lunar particle shadows and boundary layer experiments aboard the Apollo 15 and 16 subsatellites and scientific reduction and analysis of the data to date are discussed with emphasis on four major topics: solar particles; interplanetry particle phenomena; lunar interactions; and topology and dynamics of the magnetosphere at lunar orbit. The studies of solar and interplanetary particles concentrated on the low energy region which was essentially unexplored, and the studies of lunar interaction pointed up the transition from single particle to plasma characteristics. The analysis concentrated on the electron angular distributions as highly sensitive indicators of localized magnetization of the lunar surface. Magnetosphere experiments provided the first electric field measurements in the distant magnetotail, as well as comprehensive low energy particle measurements at lunar distance.

Anderson, K. A.↗
NASA NTRS1974

Particles and plasmas in the earth's magnetotail at 60 earth radii

The main purpose of this article is to describe the plasma and particle populations in the magnetotail near 60 earth radii geocentric distance. Both the plasma sheet and the high-latitude portions of the magnetotail are discussed. Electron and proton spectra at energies above about 20 keV and electron spectra down to 0.5 keV have been obtained. Another topic of importance is the comparison of the deep magnetotail plasma sheet with the Vela satellite measurements at about 20 earth radii geocentric distance.

Anderson, K. A.↗
NASA NTRS1972

Solar-wind and interplanetary electron measurements on the Apollo 15 subsatellite.

Measurements of high-energy solar-wind electrons have been made from a low orbit around the moon. Solar-wind electrons can be identified up to energies of about 3000 eV, at which an electron population of entirely different characteristics becomes dominant. The solar-wind cavity on the moon's antisolar side shows evidence of being filled by plasma coming from the downstream direction. When the direction of the interplanetary field corresponds to solar ecliptic azimuth angles of about 90 deg, a partial solar-wind cavity extends across most of the eastern sunlit side of the moon within 20 deg of the moon meridian. There are localized increases in the 500-eV electron flux over much of the sunlit hemisphere. These increases are interpreted to be the result of an interaction between the solar wind and the moon that deflects some of the solar-wind flow and results in limb shocks.

Anderson, K. A.↗
NASA NTRS1972

Subsatellite measurements of plasmas and solar particles

The experiment with the small scientific subsatellite which was launched into lunar orbit from Apollo 15 is described. The subsatellite was designed to measure plasma and energetic-particle fluxes, vector magnetic fields, and velocity of the subsatellite for determining lunar gravitational anomalies. The theory of particle-shadow formation by the moon solar wind electrons, and energetic-electron fluxes in interplanetary space are discussed along with an analysis of the initial data.

Anderson, K. A.↗
NASA NTRS1972

Subsatellite measurements of plasma and energetic particles

The Apollo 16 particles and fields subsatellite is instrumented to measure (1) plasma and energetic-particle fluxes, (2) vector magnetic fields, and (3) velocity of the subsatellite to a high precision for the purpose of determining lunar gravitational anomalies. Results from the magnetic-field and gravitational-field experiments are discussed. The results obtained from the plasma and energetic-particle detectors are discussed briefly. The plasma and energetic-particles experiment describes the various plasma regimes in which the moon moves, and determines how the moon interacts with the plasma and magnetic fields in the environment.

Anderson, K. A.↗