Details

Autor(en) / Beteiligte

• Nahar, Sultana N
• Pradhan, Anil K

Titel

Large Enhancement in High-Energy Photoionization of Fe XVII and Missing Continuum Plasma Opacity

Ist Teil von

• Physical review letters, 2016-06, Vol.116 (23), p.235003-235003, Article 235003

Ort / Verlag

United States: American Physical Society

Erscheinungsjahr

2016

Quelle

American Physical Society Journals

Beschreibungen/Notizen

• Aimed at solving the outstanding problem of solar opacity, and radiation transport plasma models in general, we report substantial photoabsorption in the high-energy regime due to atomic core photoexcitations not heretofore considered. In extensive R-matrix calculations of unprecedented complexity for an important iron ion Fe xvii (Fe^{16+}), with a wave function expansion of 99 Fe xviii (Fe^{17+}) LS core states from n≤4 complexes (equivalent to 218 fine structure levels), we find (i) up to orders of magnitude enhancement in background photoionization cross sections, in addition to strongly peaked photo-excitation-of-core resonances not considered in current opacity models, and ii) demonstrate convergence with respect to successive core excitations. The resulting increase in the monochromatic continuum, and 35% in the Rosseland mean opacity, are compared with the "higher-than-predicted" iron opacity measured at the Sandia Z-pinch fusion device at solar interior conditions.