22 research outputs found

    A new approach to analyzing solar coronal spectra and updated collisional ionization equilibrium calculations. II. Additional ionization rate coefficients

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    We have reanalyzed SUMER observations of a parcel of coronal gas using new collisional ionization equilibrium (CIE) calculations. These improved CIE fractional abundances were calculated using state-of-the-art electron-ion recombination data for K-shell, L-shell, Na-like, and Mg-like ions of all elements from H through Zn and, additionally, Al- through Ar-like ions of Fe. They also incorporate the latest recommended electron impact ionization data for all ions of H through Zn. Improved CIE calculations based on these recombination and ionization data are presented here. We have also developed a new systematic method for determining the average emission measure (EMEM) and electron temperature (TeT_e) of an isothermal plasma. With our new CIE data and our new approach for determining average EMEM and TeT_e, we have reanalyzed SUMER observations of the solar corona. We have compared our results with those of previous studies and found some significant differences for the derived EMEM and TeT_e. We have also calculated the enhancement of coronal elemental abundances compared to their photospheric abundances, using the SUMER observations themselves to determine the abundance enhancement factor for each of the emitting elements. Our observationally derived first ionization potential (FIP) factors are in reasonable agreement with the theoretical model of Laming (2008).Comment: 147 pages (102 of which are online only tables and figures). Submitted to ApJ. Version 2 is updated addressing the referee's repor

    Tensorial form and matrix elements of the relativistic nuclear recoil operator

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    Within the lowest-order relativistic approximation (∌v2/c2\sim v^2/c^2) and to first order in me/Mm_e/M, the tensorial form of the relativistic corrections of the nuclear recoil Hamiltonian is derived, opening interesting perspectives for calculating isotope shifts in the multiconfiguration Dirac-Hartree-Fock framework. Their calculation is illustrated for selected Li-, B- and C-like ions. The present work underlines the fact that the relativistic corrections to the nuclear recoil are definitively necessary for getting reliable isotope shift values.Comment: 22 pages, no figures, submitted to J. Phys.

    Air gun source instabilities and shot-by-shot signature deconvolution

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    Adaptive multiple separation based on information maximization

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    Measurement of the transverse spin dependence of the pp total cross section in the 1-3 GeV/c region

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    The pp total cross section difference between pure transverse spin states was measured in the laboratory momentum range 1-3 GeV/c. Significant differences were found and these differences show striking energy dependence. This structure is in disagreement with the predictions of simple exchange models.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22658/1/0000209.pd
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