Berlin 2005 – scientific programme
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EP: Extraterrestrische Physik
EP 6: Kosmische Strahlung und Heliosph
äre
EP 6.6: Talk
Saturday, March 5, 2005, 15:45–16:00, TU BH349
Variability of the Nitrogen Abundance in the Solar Wind and Implications for Past Solar Activity — •Robert F. Wimmer-Schweingruber1, Peter Bochsler2, Peter Wurz2, George Gloeckler3,4, Johannes Geiss5, Reinald Kallenbach5, and Thomas H. Zurbuchen4 — 1Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 11, Kiel, 24118 Germany — 2Physikalisches Institut,, University of Bern, Sidlerstr. 5, Bern, 3012 Switzerland — 3Dept. of Physics, University of Maryland, College Park, MD 20742 United States — 4University of Michigan, 2455 Hayward St., AOSS, Ann Arbor, MI 48109 — 5International Space Science Institute, Hallerstr. 6, Bern, 3012 Switzerland
The abundance of nitrogen in the heliosphere is an enigma. Laboratory analysis of lunar soils shows that trapped nitrogen is overabundant in them by about one order of magnitude relative to all noble gases, which in turn are efficiently trapped in the lunar regolith. On the other hand, the Solar Wind Ion Mass Spectrometer (SWIMS) on ACE has successfully measured the elemental abundance of nitrogen in the solar wind, N/O ≈0.121 ± 0.014, in good agreement with the photospheric value of N/O ≈ 0.123 and with the SEP-dervied coronal value. In this work we determine the abundance ratio N/Ne and investigate the variability of N/O and of N/Ne in the solar wind from 1998 to 2004. The ratios N/O and N/Ne are consistent with a constant value throughout this period of dramatically changing solar activity.