Scattering of anisotropic radiation by atoms, ions or molecules is sufficient to generate linear polarization observable in stars’ and planets’ atmospheres, circumstellar environments, and in particular in the Sun’s atmosphere. This kind of polarization is called scattering polarization (SP) or second solar spectrum (SSS) if it is formed near the limb of the solar photosphere. Generation of linear SP can typically be reached more easily than circular SP. Interestingly, the latter is often absent in observations and theories. Intrigued by this, we propose to demonstrate how circular SP can be created by anisotropic collisions if a magnetic field is present. We also demonstrate how anisotropic collisions can result in the creation of circular SP if the radiation field is anisotropic. We show that under certain conditions, linear SP creation is accompanied by the emergence of circular SP which can be useful for diagnostics of solar and astrophysical plasmas. We treat an example and calculate the density matrix elements of tensorial order k = 1 which are directly associated with the presence of circular SP. This work should encourage theoretical and observational research to be increasingly oriented towards circular SP profiles in addition to linear SP in order to improve our analysis tools of astrophysical and solar observations.

原子、离子或分子对各向异性辐射的散射足以产生可在恒星和行星大气、星际环境，特别是太阳大气中观察到的线性偏振。如果这种偏振在太阳光球的边缘附近形成，则称为散射偏振（SP）或第二太阳光谱（SSS）。线性 SP 的生成通常比圆形 SP 更容易实现。有趣的是，后者在观察和理论中经常不存在。对此很感兴趣，我们建议证明如果存在磁场，各向异性碰撞如何产生圆形 SP。我们还演示了如果辐射场是各向异性的，各向异性碰撞如何导致圆形 SP 的产生。我们表明，在某些条件下，线性 SP 的产生伴随着圆形 SP 的出现，可用于诊断太阳和天体物理等离子体。我们处理一个例子，计算张量阶的密度矩阵元素k = 1 与循环 SP 的存在直接相关。这项工作应该鼓励理论和观测研究在线性 SP 之外越来越多地面向圆形 SP 剖面，以改进我们的天体物理和太阳观测分析工具。