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

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

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

Hot ion plasma production in HIP-1 using water-cooled hollow cathodes

A steady-state ExB plasma was formed by applying a strong radially inward dc electric field near the mirror throats. Most of the results were for hydrogen, but deuterium and helium plasmas were also studied. Three water-cooled hollow cathodes were operated in the hot-ion plasma mode with the following results: (1) thermally emitting cathodes were not required to achieve the hot-ion mode; (2) steady-state operation (several minutes) was attained; (3) input powers greater than 40 kW were achieved; (4) cathode outside diameters were increased from 1.2 cm (uncooled) to 4.4 cm (water-cooled); (5) steady-state hydrogen plasma with ion temperatures from 185 to 770 eV and electron temperatures from 5 to 21 eV were produced. Scaling relations were empirically obtained for discharge current, ion temperature, electron temperature, and relative ion density as a function of hydrogen gas feed rate, magnetic field, and cathode voltage. Neutrons were produced from deuterium plasma, but it was not established whether thay came from the plasma volume or from the electrode surfaces

A Search for Biomolecules in Sagittarius B2 (LMH) with the ATCA

We have used the Australia Telescope Compact Array to conduct a search for the simplest amino acid, glycine (conformers I and II), and the simple chiral molecule propylene oxide at 3-mm in the Sgr B2 LMH. We searched 15 portions of spectrum between 85 and 91 GHz, each of 64 MHz bandwidth, and detected 58 emission features and 21 absorption features, giving a line density of 75 emission lines and 25 absorption lines per GHz stronger than the 5 sigma level of 110 mJy. Of these, 19 are transitions previously detected in the interstellar medium, and we have made tentative assignments of a further 23 features to molecular transitions. However, as many of these involve molecules not previously detected in the ISM, these assignments cannot be regarded with confidence. Given the median line width of 6.5 km/s in Sgr B2 LMH, we find that the spectra have reached a level where there is line confusion, with about 1/5 of the band being covered with lines. Although we did not confidently detect either glycine or propylene oxide, we can set 3 sigma upper limits for most transitions searched. We also show that if glycine is present in the Sgr B2 LMH at the level of N = 4 x 10^{14} cm^{-2} found by Kuan et al. (2003) in their reported detection of glycine, it should have been easily detected with the ATCA synthesized beam size of 17.0 x 3.4 arcsec^{2}, if it were confined to the scale of the LMH continuum source (< 5 arcsec). This thus puts a strong upper limit on any small-scale glycine emission in Sgr B2, for both of conformers I and II.Comment: 12 pages, 2 figures, 5 tables, accepted by MNRA