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The 2p-3d Electron Transition Multiplet of Ar +13 : A Stellar Density Diagnostic

The 2p-3d Electron Transition Multiplet of Ar +13 : A Stellar Density Diagnostic. Laura Heeter Kristina Naranjo-Rivera 2003-04. Introduction. Applications Density and temperature diagnostic for astrophysics Stellar corona, solar flairs Naturally occurring thermal plasma

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The 2p-3d Electron Transition Multiplet of Ar +13 : A Stellar Density Diagnostic

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  1. The 2p-3d Electron Transition Multiplet of Ar+13: A Stellar Density Diagnostic Laura Heeter Kristina Naranjo-Rivera 2003-04

  2. Introduction Applications • Density and temperature diagnostic for astrophysics • Stellar corona, solar flairs • Naturally occurring thermal plasma • Chandra Observatory x-ray data

  3. L-shell spectral peaks • Simple Structure • Density sensitivity (Å)

  4. Lepson et al. Survey2p-3d Ar+13 Spectral Peaks

  5. 3d15/2 3d13/2 2p23/2 Metastable State 2p13/2 Forbidden Transition Ground State 2p11/2 Trabert et al. Study • Metastable level- 9.7 ms atomic lifetime

  6. 3d15/2 3d13/2 2p23/2 Metastable State 2p13/2 Forbidden Transition Ground State 2p11/2 Theory • Dr. Ming Feng-Gu • Peak intensities will invert with increased beam current density • Increased excitation to metastable state 2p13/2 Wavelength (Å)

  7. Hypothesis • Sensitivity to beam current density • Increased electron excitation to metastable level

  8. Objective Density EBIT Ar+13 Emission Spectra Electon Beam Ion Trap Stellar Object Ar+13 Emission Spectra Density?

  9. Collector Liquid Helium Reservoir Liquid Nitrogen Reservoir Trapping Region Superconducting Helmholtz Magnet Electron Gun EBIT http://www-phys.llnl.gov/Research/EBIT/

  10. Prepare EBIT Excite Ar to Ar+13 • Determine Constant Beam Energy Collect & Analyze Spectral Images Calculate Intensity Ratios Compare Experimental and Theoretical Data Methods

  11. Results • Inverse relationship: beam current and intensity ratio

  12. Results vs. Theory Wavelength (Å)

  13. Comparison to Theoretical Models Ar+13 experimental data Monoenergetic beam Maxwellian plasma model Density (cm –3)

  14. Discussion • Increased population of metastable state occurred as beam current density increased • Accuracy promises Ar+13 as a useful density diagnostic

  15. Further Studies • Broader density range • Use other more abundant elements • Mg, Fe, Ni, and more • Currently Fe+21 is being tested

  16. Acknowledgements • The EBIT Team • Dr. Peter Beiersdorfer • Edward Magee • Dr. Hui Chen • Dr. Elmar Träbert • Ming Feng-Gu • Ms. Fruen and the Research Class

  17. The 2p-3d Electron Transition Multiplet of Ar+13: A Stellar Density Diagnostic Laura Heeter Kristina Naranjo-Rivera 2003-04

  18. Elaboration of Methods: Analyze Ar+13 Spectra • Igor Pro • N+5 calibration • Sum like data

  19. Calculate Intensity Ratios R = (I (3d5/2→2p3/2) + I (3d3/2→2p3/2)) / I(3d3/2→2p1/2)

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