December 3, 2010, 12:00 pm - 1:00 pm
December 3, 2010, 12:00 pm - 1:00 pm
Atomic Data, Modeling, and Spectroscopy of Laboratory and Astrophysical Plasmas
Arati Dasgupta (Naval Research Laboratory)
In recent years, there have been significant advances in instrumental capabilities for diagnostics measurements of astrophysical plasmas. There have been corresponding improvements in diagnostics using advanced multi-mega-ampere machines in big facilities. Analysis used in these big laboratory experiments can be used to study Inertial Confinement Fusion (ICF) and also astrophysical plasmas where laboratory measurements and simulations are the only means to interpret observed data. The astrophysical data for most cosmically abundant elements can provide a wealth of information about cosmic plasmas. State-of-the-art atomic and molecular models, along with data from space-borne experiments are needed to calibrate astrophysical models as well as to analyze and guide future experiments. These experiments will yield data that can be used to verify the completeness and accuracy of models of the emission properties of various elements involved in astrophysical processes. These improved models in turn will allow scientists to refine theories about the behavior of plasmas and highly charged ions--essentially, our basic understanding of matter in extreme environments. Proper analysis requires accurate atomic data and kinetics calculations which must include all relevant atomic processes such as dielectronic recombination. I will also discuss needs in dielectronic recombination data motivated by recent work directed at a quantitative understanding of ion charge states of various elements observed in situ in the solar wind and CMEs. The competing processes of ionization and recombination lead to departures from collision ionization equilibrium. The use of this as a diagnostic of acceleration and heating processes of the solar wind and CMEs is sensitive to the accuracy of the atomic rates in a way that steady state ionization equilibrium plasmas are not. The most pressing need is dielectronic recombination rates for ions Fe 8+ - Fe 12+ . These are among the dominant species observed in various regions of the solar wind and CMEs, and in remotely sensed EUV spectra.