Title: A numerical approach for modelling the polarisation signals of strong resonance lines with partial frequency redistribution. Numerical applications to two-term atoms and plane-parallel atmospheres Show Chinese title

Title: 一种用于模拟具有部分频率重分布的强共振线极化信号的数值方法。数值应用于二项原子和平面平行大气

Abstract: Aims. The main goal of this paper is to present an accurate and efficient numerical strategy for solving the radiative transfer problem for polarised radiation in strong resonance lines forming out of local thermodynamic equilibrium, taking angle-dependent (AD) partial frequency redistribution (PRD) effects and J-state interference into account. We consider the polarisation produced both by the Zeeman effect and by the scattering of anisotropic radiation, along with its sensitivity to the Hanle and magneto-optical effects. Methods. We introduce a formalism that allows treating both a two-level and a two-term atom in the presence of arbitrary magnetic and bulk velocity fields. The problem is formulated by treating the population of the lower level/term as a fixed input parameter. This approach makes the problem linear with respect to the radiation field, enabling the application of efficient matrix-free preconditioned iterative methods for its solution. Additionally, the computation of the scattering emissivity in the comoving frame, together with a careful choice of the angular and spectral quadrature nodes, allow us to speed up the calculations by reducing the number of evaluations of the redistribution functions. Results. The proposed solution strategy is applied to synthesise the Stokes profiles of the Mg ii h&k doublet and the H i Ly-{\alpha} line in 1D semi-empirical models. The results demonstrate that the method is both fast and accurate. A comparison with calculations from HanleRT-TIC displays an overall good agreement, thereby validating our solution strategy. Moreover, for the wavelength-integrated polarisation profiles of the H i Ly-{\alpha} line, we find an excellent agreement between the results obtained including PRD effects in their general AD description and those obtained considering the angle-averaged simplifying approximation. Show Chinese abstract

Abstract: 目标。 本文的主要目的是提出一种准确且高效的数值策略，用于解决在局部热动平衡外形成的强共振线中的偏振辐射传输问题，同时考虑角度依赖的（AD）部分频率重分布（PRD）效应和J态干涉。 我们考虑由塞曼效应和各向异性辐射散射产生的偏振，以及它对汉勒效应和磁光效应的敏感性。 方法。 我们引入了一种形式主义，可以在存在任意磁场和整体速度场的情况下处理两级和两态原子的问题。 通过将低能级/项的群体视为固定输入参数来制定该问题。 这种方法使得该问题相对于辐射场是线性的，从而可以应用有效的矩阵自由预条件迭代方法来解决问题。 此外，共动框架中散射发射率的计算，加上角和谱四边形节点的仔细选择，使我们能够通过减少重分布函数的评估次数来加速计算。 结果。 所提出的解决方案策略被应用于合成Mg ii h&k双线和H i Ly-{\alpha }线在1D半经验模型中的斯托克斯轮廓。 结果显示该方法既快速又准确。 与HanleRT-TIC的计算结果相比，总体上显示出了很好的一致性，从而验证了我们的解决方案策略。 此外，对于H i Ly-{\alpha }线的波长积分偏振轮廓，我们在包括PRD效应的一般AD描述下获得的结果与考虑角度平均简化近似下的结果之间发现了极好的一致性。