2005 Fiscal Year Final Research Report Summary
Collisions of highly charged ions with relativistic effects by electron impact in plasmas
| Project/Area Number |
14580521
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
プラズマ理工学
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| Research Institution | University of Miyazaki |
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Principal Investigator |
NAKAZAKI Shinobu University of Miyazaki, Faculty of Engineering, professor, 工学部, 教授 (70041001)
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| Co-Investigator(Kenkyū-buntansha) |
OHSAKI Akihiko University of Miyazaki, Faculty of Engineering, professor, 工学部, 教授 (70223782)
IGARASHI Akinori University of Miyazaki, Faculty of Engineering, associate professor, 工学部, 助教授 (90300855)
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| Project Period (FY) |
2002 – 2005
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| Keywords | highly charged ion / excitation cross section / rate coefficient / R-matrix method / Dirac equation / Breit-Pauli approximation / H-like ion / He-like ion |
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| Research Abstract |
Emissions from ion in plasmas and excitation cross sections of the ion by electron impact can be used to obtain electron temperature and density for plasma diagnostics. The aim of this project is to study relativistic effects for excitation cross sections of ions by electron impact. We used three kinds of R-matrix methods viz. non-relativistic R-matrix (RMAT), semi-relativistic R-matrix (BPRMAT) with the Breit-Pauri approximation and full relativistic R-matrix (DRMAT) with the Dirac approximation.
Present theoretical results are available to use as input data on a collisional radiative model for plasma diagnostics. The results are summarized as follows.
1. The electron-impact transitions between the n=2 fine-structure levels of hydrogenic ions were calculated using the DRMAT, the close-coupling and the Coulomb-Born approximations. It was found that the electron-exchange effect was a considerable contribution to the cross-section of optically forbidden transitions.
2. Cross sections and rate coefficients for electron-impact excitation of He-like ions (Z=16-26) were calculated by use of the DRMAT, the BPRMAT and the RMAT. The lowest 45 target levels were included in the calculation to obtain the rate coefficients for the ground state to the excited states with n=2, 3 and 4. It was verified that the effects of coupling and resonances from n=5 levels play an important role in rate coefficients for the transitions to the n=4 levels.
3. Excitation cross sections and Stokes parameters of Li-like and Mg-like ions, and Ca were obtained by using the RMAT and BPRMAT. It was shown that present results were in excellent agreement with the experiments and reliable for plasma diagnostics.
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