Tungsten Ions in Plasmas: Statistical Theory of Radiative-Collisional Processes

Atoms

Alexander V. Demura¹  Mikhail B. Kadomtsev¹  Valery S. Lisitsa¹  Vladimir A. Shurygin¹ 

[1]National Research Center “Kurchatov Institute”, Academician Kurchatov square 1, Moscow 123182, Russia

[2] E-Mails:

关键词: plasma;    tungsten;    Thomas-Fermi model;    equivalent photon flux;    plasma oscillations;    ionization cross-sections;    radiation losses;    corona limit;   

DOI  :  10.3390/atoms3020162

来源: mdpi

【 摘 要 】

The statistical model for calculations of the collisional-radiative processes in plasmas with tungsten impurity was developed. The electron structure of tungsten multielectron ions is considered in terms of both the Thomas-Fermi model and the Brandt-Lundquist model of collective oscillations of atomic electron density. The excitation or ionization of atomic electrons by plasma electron impacts are represented as photo-processes under the action of flux of equivalent photons introduced by E. Fermi. The total electron impact single ionization cross-sections of ions W^k+ with respective rates have been calculated and compared with the available experimental and modeling data (e.g., CADW). Plasma radiative losses on tungsten impurity were also calculated in a wide range of electron temperatures 1 eV–20 keV. The numerical code TFATOM was developed for calculations of radiative-collisional processes involving tungsten ions. The needed computational resources for TFATOM code are orders of magnitudes less than for the other conventional numerical codes. The transition from corona to Boltzmann limit was investigated in detail. The results of statistical approach have been tested by comparison with the vast experimental and conventional code data for a set of ions W^k+. It is shown that the universal statistical model accuracy for the ionization cross-sections and radiation losses is within the data scattering of significantly more complex quantum numerical codes, using different approximations for the calculation of atomic structure and the electronic cross-sections.

【 授权许可】

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