A plasma under the influence of an external magnetic field changes the optical properties due to the Zeeman splitting of the energy levels. This splitting degenerates an initial single spectral line into a system of spectral lines with different transition frequencies defined by the electronic structure of the energy levels. Newly created magnetic sub-levels redefine the spectral profile of the line emission and therefore radiation transport mechanism in optically thick plasma. Self-absorption which defines the excited state-densities is an important mechanism and can be used with other methods to describe the state densities for an optically thick plasma. This method is an established tool to retrieve state-density and plasma parameters. To measure each magnetic sub-level density of argon 1s4 and 1s5 (in Paschen's notation) a tunable diode laser absorption spectroscopy (TDLAS) was used. Based on reconstructed excited state densities, the self-absorption coefficient was calculated for individual magnetic sub-levels. A decrease in self-absorption with an external magnetic field was noticed indicating a higher transparency of the plasma. Furthermore a polarization dependent self-absorption was found. The presented results can help to model optical properties and interpret the absorption of a low-pressure optically thick magnetized plasma.

中文翻译：

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磁化瞬态低压等离子体的光学特性

由于能级的塞曼分裂，在外部磁场影响下的等离子体会改变光学特性。这种分裂将初始的单个谱线退化为具有由能级的电子结构定义的不同跃迁频率的谱线系统。新创建的磁性子能级重新定义了线发射的光谱轮廓，从而重新定义了光学厚等离子体中的辐射传输机制。定义激发态密度的自吸收是一种重要的机制，可以与其他方法一起使用来描述光学厚等离子体的状态密度。该方法是检索状态密度和等离子体参数的成熟工具。测量氩气 1s4 和 1s5（在 Paschen' s 符号）使用可调谐二极管激光吸收光谱 (TDLAS)。基于重建的激发态密度，计算了各个磁子能级的自吸收系数。注意到随着外部磁场的自吸收减少，表明等离子体的透明度更高。此外还发现了偏振相关的自吸收。所呈现的结果有助于模拟光学特性并解释低压光学厚磁化等离子体的吸收。此外还发现了偏振相关的自吸收。所呈现的结果有助于模拟光学特性并解释低压光学厚磁化等离子体的吸收。此外还发现了偏振相关的自吸收。所呈现的结果有助于模拟光学特性并解释低压光学厚磁化等离子体的吸收。