Engineering topics

Frank, Louis A.

Publications and source records attributed to Frank, Louis A..

8 records

NASA NTRS1995

Analysis of plasma measurements for the Geotail mission

The first phase of the Geotail mission, an exploration of the distant magnetotail, was successfully concluded in October 1994. Geotail is currently engaged in a survey of plasmas at distances from Earth approximately 10 to 30 R(sub E). Throughout the mission the Comprehensive Plasma Instrumentation has functioned well with successful return of data. The analysis of the CPI measurements has resulted in a series of publications, and research efforts are ongoing. Research topics include interaction of the magnetotail with the fields and plasmas of the solar wind, steady-state magnetic reconnection in the distant magnetotail at a neutral line bounded by a pair of slow-mode magnetohydrodynamic shocks, development and evolution of plasmoids in magnetotail and magnetospheric substorms, and cold ion beams coexisting as distinct components in the presence of hot plasma-sheet plasmas.

Frank, Louis A.↗

NASA NTRS1994

Comprehensive Plasma Instrumentation (CPU) for the Geotail spacecraft

Geotail was launched on 24 July 1992 as the first new spacecraft of the International Solar Terrestrial Physics Program (ISTP). A primary objective of the Geotail mission is the acquisition of particles and fields measurements in the tail region of the magnetosphere. Some of the specific scientific objectives of the Geotail mission are; (1) assessment of the relative importance of solar-wind and ionospheric sources to the plasmas of the magnetotail, (2) a search for plasmoids and flux ropes, (3) direct observation of the effects of plasma acceleration and heating in the current sheet, and (4) measurements of currents and convective flows carried by magnetotail plasmas. The Comprehensive Plasma Instrumentation (CPI) aboard the Geotail spacecraft provides observations of the charged particles that comprise the plasma populations of the magnetosphere and the solar wind. In many cases the physical processes that contribute to the flow of energy and mass through the Solar-Terrestrial plasma system can be understood only through a detailed examination and analysis of the distribution of the particle velocities in the ambient plasmas. The CPI provides detailed measurements of these distributions. It employs three plasma analyzers: (1) the Hot Plasma analyzer (CPI-HP) for hot electrons and ions found in the plasma sheet and the inner magnetosphere; (2) a Solar Wind analyzer (CPI-SW) for cool plasmas with high bulk speeds such as those found in the solar wind and magnetosheath; and (3) an Ion Composition analyzer (CPI-IC) for identification of ion species such as H(+), He(+), He(++), and O(+). Along with measurements from other fields and particles instrumentation on Geotail, the CPI measurements provide a fundamental experimental base for investigations of solar-terrestrial plasmas and fields.

Frank, Louis A.↗

NASA NTRS1994

Analysis of plasma measurements for the Geotail mission

The CPI plasma measurements from the Geotail spacecraft are currently used by a number of scientists in support of varied research projects. Measurements from the CPI hot plasma analyzer have been processed to compute one-minute averages of plasma densities, temperatures, and velocities for the period 1 Oct. 1992 - 31 July 1993. These parameters are used in a preliminary survey of the magnetotail for distances from earth of 10 to 210 earth radii. The cold plasmas within the magnetotail drift towards the midplane and are thought to be a principal source for the hot plasma sheet. A remarkable result from Geotail is the observation of cold ion beams coexisting as distinct components in the presence of hot plasma-sheet plasmas. The development and evolution of plasmoids is a topic of considerable interest in studies of the magnetotail and magnetospheric substorms. A number of possible plasmoids have been identified in the Geotail data set based upon reversals of the Z component of the magnetic field as observed with the MGF instrumentation. An intensive study of the electron and ion velocity distributions and the plasma parameters for several of these events reveals unexpected features. Collaborative work with several Geotail instrument teams and other researchers is also ongoing.

Frank, Louis A.↗

NASA NTRS1994

Analysis of plasma measurements for the Geotail mission

Data processing and research efforts for the period October 1993 to September 1994 are reported. Routine data processing includes the production of color spectrograms and computing of quantitative plasma parameters such as the plasma number density, bulk flow velocity, temperature, and pressure. In addition, specialized analysis software is being developed for specific and general applications. Research activities include the measurement of plasmas from the Geotail spacecraft; the processing of the measurements from a hot plasma analyzer to compute one minute averages of plasma densities, temperatures, and velocities for a substantial part of the Geotail deep tail mission; and, a preliminary survey of the magnetotail for geocentric radial distances of 10 to 210 earth radii. The topology of the magnetotail with its various regions and boundaries is determined by a complex interaction with the fields and plasmas of the solar wind. Observations of the rotation of the magnetic field in the solar wind show that it is well correlated with repeated transitions at Geotail from the magnetotail lobe to a magnetosheath-like boundary layer.

Frank, Louis A.↗

NASA NTRS1991

Report of the magnetospheric physics panel

Magnetospheric research is a relatively new area in the study of the Earth's environment. The present report attempts to overview past and future research on this topic. The goals of magnetospheric research are numerous, and include: understanding large scale magnetospheres of the Earth and other planets; understanding the plasma physical processes operating within the various magnetospheres; to understand how mass, energy and momentum are transmitted from the solar wind; to understand quantitatively the coupling between magnetospheres and their ionospheres; and to understand the magnetospheric mechanisms which accelerate particles to high energies, as well as the ultimate fate of these particles. The report continues on to summarize a number of proposed space missions aimed at data acquisition. Finally, there is a brief discussion of the theory and modeling of magnetospheres.

Burch, James L.↗

NASA NTRS1990

Project ERIC - The search for environmental reactions induced by comets

A sounding rocket experiment was conducted to release molecules of H2O and CO2 into the daytime ionosphere within the simultaneous fields of view of the Millstone Hill radar and the Dynamics Explorer UV imager. Preliminary results confirm the creation of chemically-induced F-region plasma depletions and reduced UV intensities from the modified region.

Mendillo, Michael↗

NASA NTRS1989

Measurements of the diffuse ultraviolet radiation

The imaging instrumentation on the Dynamics Explorer 1 satellite has been used to measure the intensity of the diffuse ultraviolet radiation on two great circles about the sky. It is found that the isotropic component of the diffuse ultraviolet radiation (possibly of extragalactic origin) has an intensity of 530 + or - 80 units (a unit is 1 photon per sq cm s A sr) at a wavelength of 150 nm. The Galactic component of the diffuse ultraviolet radiation has a dependence on Galactic latitude which requires strongly forward scattering particles if it is produced by dust above the Galactic plane.

Fix, John D.↗

NASA NTRS1986

Mars Aeronomy Observer: Report of the Science Working Team

The Mars Aeronomy Observer (MAO) is a candidate follow-on mission to Mars Observer (MO) in the Planetary Observer Program. The four Mariner and two Viking spacecraft sent to Mars between 1965 and 1976 have provided a wealth of information concerning Martian planetology. The Mars Observer, to be launched in 1990, will build on their results by further examining the elemental and mineralogical composition of the surface, the strength and multipolar composition of the planetary magnetic field, the gravitational field and topography, and the circulation of the lower atmosphere. The Mars Aeronomy Observer is intended to address the last major aspects of Martian environment which have yet to be investigated: the upper atmosphere, the ionsphere, and the solar wind interaction region.

Hunten, Donald M.↗