Parametric dependence of ion temperature and relative density in the NASA Lewis SUMMA facility

Further hot-ion plasma experiments were conducted in the SUMMA superconducting magnetic mirror facility. A steady-state ExB plasma was formed by applying a strong radially inward dc electric field between cylindrical anodes and hollow cathodes located near the magnetic mirror maxima. Extending the use of water cooling to the hollow cathodes, in addition to the anodes, resulted in higher maximum power input to the plasma. Steady-state hydrogen plasmas with ion kinetic temperatures as high as 830 eV were produced. Functional relations were obtained empirically among the plasma current, voltage, magnetic flux density, ion temperature, and relative ion density. The functional relations were deduced by use of a multiple correlation analysis. Data were obtained for midplane magnetic fields from 0.5 to 3.37 tesla and input power up to 45 kW. Also, initial absolute electron density measurements are reported from a 90 deg Thomson scattering laser system

Interplanetary mission design handbook. Volume 1, part 2: Earth to Mars ballistic mission opportunities, 1990-2005

Graphical data necessary for the preliminary design of ballistic missions to Mars are provided. Contours of launch energy requirements, as well as many other launch and Mars arrival parameters, are presented in launch date/arrival date space for all launch opportunities from 1990 through 2005. In addition, an extensive text is included which explains mission design methods, from launch window development to Mars probe and orbiter arrival design, utilizing the graphical data as well as numerous equations relating various parameters

Shock tube measurements of growth constants in the branched-chain ethane-carbon monoxide-oxygen system

Exponential free radical growth constants have been measured for ethane carbon monoxide oxygen mixtures by monitoring the growth of oxygen atom concentration as manifested by CO flame band emission. Data were obtained over the temperature range of 1200 to 1700 K. The data were analyzed using an ethane oxidation mechanism involving seven elementary reaction steps. Calculated growth constants were close to experimental values at lower temperatures, up to about 1400 K, but at higher temperatures computed growth constants were considerably smaller than experiment. In attempts to explain these results additional branching reactions were added to the mechanism. However, these additional reactions did not appreciably change calculated growth constants

Flow and thermal effects in continuous flow electrophoresis

In continuous flow electrophoresis the axial flow structure changes from a fully developed rectilinear form to one characterized by meandering as power levels are increased. The origin of this meandering is postulated to lie in a hydrodynamic instability driven by axial (and possibly lateral) temperature gradients. Experiments done at MSFC show agreement with the theory

Understanding Heisenberg's 'Magical' Paper of July 1925: a New Look at the Calculational Details

In July 1925 Heisenberg published a paper [Z. Phys. 33, 879-893 (1925)] which ended the period of `the Old Quantum Theory' and ushered in the new era of Quantum Mechanics. This epoch-making paper is generally regarded as being difficult to follow, perhaps partly because Heisenberg provided few clues as to how he arrived at the results which he reported. Here we give details of calculations of the type which, we suggest, Heisenberg may have performed. We take as a specific example one of the anharmonic oscillator problems considered by Heisenberg, and use our reconstruction of his approach to solve it up to second order in perturbation theory. We emphasize that the results are precisely those obtained in standard quantum mechanics, and suggest that some discussion of the approach - based on the direct computation of transition amplitudes - could usefully be included in undergraduate courses in quantum mechanics.Comment: 24 pages, no figures, Latex, submitted to Am. J. Phy

Planetary geometry handbook: Venus positional data, 1988 - 2020, volume 2

Graphical data necessary for the analysis of planetary exploration missions to Venus are presented. Positional and geometric information spanning the time period from 1988 through 2020 is provided. The data and the usage are explained

Planetary geometry handbook: Mars positional data, 1990 - 2020, volume 3

Graphical data necessary for the analysis of planetary exploration missions to Mars are presented. Positional and geometric information spanning the time period from 1990 through 2020 is provided. The data and usage are explained