The Sun and other stars are magnetic: magnetism pervades their interiors and affects their evolution in a variety of ways. In the Sun, both the fields themselves and their influence on other phenomena can be uncovered in exquisite detail, but these observations sample only a moment in a single star’s life. By turning to observations of other stars, and to theory and simulation, we may infer other aspects of the magnetism—e.g., its dependence on stellar age, mass, or rotation rate—that would be invisible from close study of the Sun alone. Here, we review observations and theory of magnetism in the Sun and other stars, with a partial focus on the “Solar-stellar connection”: i.e., ways in which studies of other stars have influenced our understanding of the Sun and vice versa. We briefly review techniques by which magnetic fields can be measured (or their presence otherwise inferred) in stars, and then highlight some key observational findings uncovered by such measurements, focusing (in many cases) on those that offer particularly direct constraints on theories of how the fields are built and maintained. We turn then to a discussion of how the fields arise in different objects: first, we summarize some essential elements of convection and dynamo theory, including a very brief discussion of mean-field theory and related concepts. Next we turn to simulations of convection and magnetism in stellar interiors, highlighting both some peculiarities of field generation in different types of stars and some unifying physical processes that likely influence dynamo action in general. We conclude with a brief summary of what we have learned, and a sampling of issues that remain uncertain or unsolved.

太阳和其他恒星具有磁性：磁性遍布其内部，并以多种方式影响其演化。在太阳中，场本身及其对其他现象的影响都可以以精致的细节被发现，但这些观测仅采样了单个恒星生命中的一个时刻。通过转向对其他恒星的观测、理论和模拟，我们可以推断出磁性的其他方面——例如，它对恒星年龄、质量或旋转速度的依赖——而仅靠对太阳的仔细研究是看不到这些的。在这里，我们回顾了太阳和其他恒星的磁性观测和理论，部分关注“太阳与恒星的联系”：即对其他恒星的研究影响了我们对太阳的理解，反之亦然。我们简要回顾了可以测量恒星中磁场（或以其他方式推断其存在）的技术，然后重点介绍通过此类测量发现的一些关键观测发现，重点关注（在许多情况下）那些对如何测量恒星磁场的理论提供特别直接限制的技术。建造和维护田地。然后我们讨论不同物体中场如何产生：首先，我们总结对流和发电机理论的一些基本要素，包括对平均场理论和相关概念的非常简短的讨论。接下来，我们转向对恒星内部的对流和磁性的模拟，强调不同类型恒星中场生成的一些特性以及一些可能影响一般发电机作用的统一物理过程。最后，我们简要总结了我们所学到的知识，以及一些仍然不确定或未解决的问题。