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A resolution to the low temperature electron recombination problem for astrophysical plasmas.
Completed
Description
Recent and ongoing work on electron recombination of atomic systems has revealed a range of ions where rates are underestimated or overestimated, sometimes by an order of magnitude, due to the positioning of resonance(s) near to the ground state threshold. Consequently, these ion stages may have a significant effect on diagnostics of abundances, temperatures, and densities. We propose to (1) implement a new type of survey calculation to identify which ions exhibit sensitivity to near threshold resonances; (2) quantify the resulting uncertainties in the DR rates for these ion stages; (3) show that the recently proposed process of "below threshold DR" can provide accurate rate coefficients for ions with critical sensitivity to near threshold resonances, and (4) archive and release these rates for use in astrophysical spectral studies. To achieve these results we will use a range of methods to calculate electron recombination, including both semi- and fully-relativistic approaches. The new theory for the inclusion of below threshold recombination was recently derived in the literature and will be used in this proposal. The work would be of significance for a range of NASA objectives and missions. These would include the analysis of low temperature photo-ionized plasmas. It would determine the atomic systems for which the low temperature recombination rate coefficients can be used with confidence, and provides a means to remove the sensitivity of the remaining rate coefficients to their near threshold resonances. As such it would lead to an improved understanding of these plasmas and their role in the cosmos.
Details
| Technology area | Sensors and Instruments > In Situ Instruments and Sensors > Field and Particle Detectors |
| Program | Astrophysics Research and Analysis (APRA) |
| Start date | 2015-08-01 |
| End date | 2018-07-31 |
Project contacts
Listed on TechPort itself — the most direct way to ask about this specific project.
- Stuart D Loch
- John M Mason
- Michael S Pindzola
How to get involved
This is a mature technology (TRL 7+) — the realistic path in is usually NASA's Technology Transfer Program: licensing an existing NASA patent, or a Space Act Agreement to use NASA facilities/expertise directly. NASA also runs a startup licensing program with no upfront fee for companies formed to commercialize a specific NASA technology.
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