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Swartz, W. E.

Publications and source records attributed to Swartz, W. E..

31 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Photoelectron escape from the ionosphere of Jupiter

Photoelectron escape fluxes and ambient electron heating from the Jovian ionosphere are computed as a function of local time and latitude. Several differences for the fluxes expected from a hydrogen atmosphere, rather than a terrestrial type of atmosphere, are described, including an increase in structure in the energy spectra due to the paucity of ionic states entering the photo-ionization processes and lower escape fluxes above 10 eV than were expected from a simple scaling of earth fluxes.

Swartz, W. E.↗
NASA NTRS1973

Thermalization and transport of photoelectrons - A comparison of theoretical approaches.

Three methods of studying ionospheric photoelectron thermalization, in which transport effects are evaluated in different ways, are outlined and compared. One method uses a diffusion equation formulation, the second proceeds from a two-stream approximation to the general particle transfer equation, and the third employs a Monte Carlo technique to simulate electron paths. The methods are compared by applying them to identically prepared models. The methods are in close agreement for altitudes in the region of local energy loss, but higher altitudes reveal a discrepancy of as much as a factor of 2 in the net flux of photoelectrons. The discrepancy is removed by appropriately modifying the computational techniques.

Cicerone, R. J.↗
NASA NTRS1973

Incompatibility of solar EUV fluxes and incoherent scatter measurements at Arecibo.

Photoionization rates have been calculated from recent solar EUV flux measurements and are compared with the electron-ion recombination rates estimated from electron density profiles and current reaction rates. These photoionization rates also provided the first step in calculating the photoelectron heating rates of the ambient electrons, which are compared with the cooling rates deduced from ion and electron temperature measurements at Arecibo. The effects of changes in the assumed neutral models, the rate coefficients, and the temperature measurements are discussed. Comparisons of the profiles of energy input and loss with similar profiles of ion production and recombination suggest that the solar EUV fluxes have been underestimated. These comparisons also imply lower molecular neutral densities in winter than in summer.

Swartz, W. E.↗
NASA NTRS1972

The global energy budget of the thermosphere.

Experimental neutral atmospheric density and temperature profiles can be used to calculate the energy content variations of a given region as a function of time, season and location for which the data are available. Such calculations may then be compared with estimated energy inputs and losses to determine what other mechanisms may be important. In the present paper a model based on both incoherent scatter data from Arecibo, Nancay, and Jicamarca and satellite density measurements is used to derive the global distributions of thermal energy content and losses in the thermosphere. The energy sources and transport mechanisms required for global thermal balance are then discussed.

Swartz, W. E.↗
NASA NTRS1971

Analytic expression for the energy-transfer rate from photoelectrons to thermal-electrons.

An analytic form is given for the energy-transfer rate from photoelectrons to thermal electrons. The expression fits the classical formulation of Itakawa and Aono (1966) at low energies and gives a smooth transition to fit the quantum mechanical equation of Schunk and Hays (1971) at higher energies. The corresponding loss function or stopping power has a form that is convenient in auroral and dayglow calculations.

Swartz, W. E.↗