Magnetic winding is a fundamental topological quantity that underpins magnetic helicity and measures the entanglement of magnetic field lines. Like magnetic helicity, magnetic winding is also an invariant of ideal magnetohydrodynamics. In this article, we give a detailed description of what magnetic winding describes, how to calculate it and how to interpret it in relation to helicity. We show how magnetic winding provides a clear topological description of magnetic fields (open or closed) and we give examples to show how magnetic winding and helicity can behave differently, thus revealing different and important information about the underlying magnetic field.

中文翻译：

---

磁性绕组：它是什么以及它有什么好处？

磁绕组是一个基本的拓扑量，它支持磁螺旋度并测量磁场线的纠缠。与磁螺旋性一样，磁绕组也是理想磁流体动力学的不变量。在本文中，我们详细描述了磁性绕组所描述的内容、如何计算它以及如何解释它与螺旋度的关系。我们展示了磁性绕组如何提供磁场（开放或封闭）的清晰拓扑描述，并举例说明磁性绕组和螺旋性如何表现不同，从而揭示有关底层磁场的不同且重要的信息。