The influence of autoionization accompanied by excitation on dielectronic recombination and ionization equilibrium. [in high temperature astrophysical plasmas]
The influence of autoionization accompanied by excitation on dielectronic recombination and ionization equilibrium. [in high temperature astrophysical plasmas]
复制标题
激发伴随的自电离对双电子复合和电离平衡的影响。
DOI：
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发表时间：
1977
期刊：
影响因子：
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通讯作者：
M. Blaha
中科院分区：
文献类型：
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作者：
V. Jacobs;J. Davis;P. Kepple;M. Blaha
在双电子复合过程中，由无辐射俘获形成的双激发态可优先自电离为复合离子的激发态。这一额外的自电离过程在以前的双电子复合处理中没有讨论过。某些非氢化铁离子的双电子复合速率虽然仍然大于直接辐射复合速率，但通过在稳定辐射跃迁的分支比中加入额外的自电离率而显著降低。因此，最大平衡丰度的温度明显低于最近的计算结果。最后，计算了高温等离子体中电子-铁离子碰撞辐射过程的辐射能量损失率系数。在含有大量束缚电子的稳态等离子体中，共振线辐射的电子碰撞激发是主要的辐射冷却机制。然而，研究发现，在双电子复合过程中发射的辐射可能比直接复合辐射和韧致辐射更重要。
In the process of dielectronic recombination, the doubly excited state formed by radiationless capture may autoionize preferentially into an excited state of the recombining ion. This additional autoionization process has not been discussed in previous treatments of dielectronic recombination. The dielectronic recombination rates for certain nonhydrogenic Fe ions, although still larger than the direct radiative recombination rates, are found to be substantially reduced by the inclusion of the additional autoionization rate in the branching ratio for the stabilizing radiative transition. Consequently, the temperatures of maximum equilibrium abundance are significantly lower than those predicted by recent calculations. Finally, the radiative energy loss rate coefficients are calculated for radiation processes involving electron Fe-ion collisions in high-temperature plasmas. Electron impact excitation of resonance line radiation is the dominant radiative cooling mechanism in steady-state plasmas at temperatures where ions with bound electrons are abundant. However, it is found that the radiation emitted during dielectronic recombination can be more important than direct recombination radiation and bremsstrahlung.