Influence Of The Multipole Effects To The Opacity Of Hot And Dense Plasmas

Radiative opacity of plasmas is an important parameter, which couples into the equation of radiative transportation and affect strikingly the radiative transportation process of hot plasmas, as well as a crucial factor for the design of nuclear weapons. With the development of the theory of atomic structure and computer technology, in addition to the progress of experiment, the calculation of opacity is approaching higher accuracy and reliability. Now there are mostly four theoretical models established for the calculation of opacity: AA(average atom), STA(super transition arrays), UTA (unresolved transition array) and DTA (detailed term accounting). The DTA model has the highest accuracy and the most expensive computational cost in the above four models, which can be used for the calculation of the lighter elements but encounter difficulties in the calculation of heavy elements. Compared with other models, the AA model has the smallest computation cost but a coarser result. As for hot dense plasma of heavy elements, the calculation using AA model can not only guarantee acceptable precision but also reduce the computation cost compared with the DTA model. In this thesis, the contribution of electric quadrupole (E2) and higher pole transitions to the opacity of hot and dense plasmas of element aurum is taken into account by using an average-atom model. The influence of the bound-bound transition due to the E2, E3, and E4 transition is calculated and discussed respectively depending on density and temperature. Influence of the retardation to the calculation is discussed. And the dependence of the n, 1 to the multipole effects is investigated.