Electron Impact Excitation and Dielectronic Recombination of Highly Charged Tungsten Ions

Atoms

Zhongwen Wu²  Yanbiao Fu²  Xiaoyun Ma²  Maijuan Li²  Luyou Xie²  Jun Jiang²  Chenzhong Dong¹  Alfred Müller²  Bastiaan J. Braams²  Peter Beiersdorfer² 

[1] Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China;

关键词: electron impact excitation;    dielectronic recombination;    highly charged tungsten ions;    DR rate coefficients;    degree of linear polarization;   

DOI  :  10.3390/atoms3040474

来源: mdpi

【 摘 要 】

Electron impact excitation (EIE) and dielectronic recombination (DR) of tungsten ions are basic atomic processes in nuclear fusion plasmas of the International Thermonuclear Experimental Reactor (ITER) tokamak. Detailed investigation of such processes is essential for modeling and diagnosing future fusion experiments performed on the ITER. In the present work, we studied total and partial electron-impact excitation (EIE) and DR cross-sections of highly charged tungsten ions by using the multiconfiguration Dirac–Fock method. The degrees of linear polarization of the subsequent X-ray emissions from unequally-populated magnetic sub-levels of these ions were estimated. It is found that the degrees of linear polarization of the same transition lines, but populated respectively by the EIE and DR processes, are very different, which makes diagnosis of the formation mechanism of X-ray emissions possible. In addition, with the help of the flexible atomic code on the basis of the relativistic configuration interaction method, DR rate coefficients of highly charged W ions are also studied, because of the importance in the ionization equilibrium of tungsten plasmas under running conditions of the ITER.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.