SUPPRESSION OF DIELECTRONIC RECOMBINATION DUE TO FINITE DENSITY EFFECTS
SUPPRESSION OF DIELECTRONIC RECOMBINATION DUE TO FINITE DENSITY EFFECTS
复制标题
由于有限密度效应而抑制介电复合
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
N. Badnell
中科院分区：
文献类型：
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作者：
D. Nikolić;D. Nikolić;T. Gorczyca;K. Korista;G. J. Ferland;N. Badnell
我们已经开发了一个通用的模型来确定密度相关的有效的双电子复合（DR）率系数，以探讨有限密度对等离子体电离平衡的影响。我们的模型包括乘一个抑制因子，这些高精度的总零密度DR率系数已产生的国家的最先进的理论计算，并已通过实验基准。抑制因子是基于早期详细的碰撞辐射计算，这是在各种密度和温度的广泛的离子，但使用了一个简化的治疗DR。一般的抑制公式，然后开发作为一个函数的等电子序列，电荷，密度和温度。这些密度相关的有效DR速率系数然后被用于等离子体模拟代码Cloudy中，以计算碰撞电离和光电离等离子体在非常低（ne = 1 cm−3）和有限（ne = 1010 cm−3）密度下的电离平衡曲线。我们发现，更密集的情况下，是显着更多的电离，由于抑制DR，通过详细的碰撞辐射计算，利用国家的最先进的部分DR率系数，进一步研究DR的密度效应。预计这将影响在稠密的宇宙气体，如那些在新星和超新星壳，吸积盘，以及在活动星系核广泛的发射线区域的电离平衡的预测。
We have developed a general model for determining density-dependent effective dielectronic recombination (DR) rate coefficients in order to explore finite-density effects on the ionization balance of plasmas. Our model consists of multiplying by a suppression factor those highly-accurate total zero-density DR rate coefficients which have been produced from state-of-the-art theoretical calculations and which have been benchmarked by experiment. The suppression factor is based upon earlier detailed collision-radiative calculations which were made for a wide range of ions at various densities and temperatures, but used a simplified treatment of DR. A general suppression formula is then developed as a function of isoelectronic sequence, charge, density, and temperature. These density-dependent effective DR rate coefficients are then used in the plasma simulation code Cloudy to compute ionization balance curves for both collisionally ionized and photoionized plasmas at very low (ne = 1 cm−3) and finite (ne = 1010 cm−3) densities. We find that the denser case is significantly more ionized due to suppression of DR, warranting further studies of density effects on DR by detailed collisional-radiative calculations which utilize state-of-the-art partial DR rate coefficients. This is expected to impact the predictions of the ionization balance in denser cosmic gases such as those found in nova and supernova shells, accretion disks, and the broad emission line regions in active galactic nuclei.