In his seminal book on electromagnetism, Purcell presented a conceptually rich discussion in which he used Lorentz contraction to relate the electromagnetic fields of a current-carrying wire when observed from different inertial frames. In a recent paper D’Abramo (2020 Eur . J . Phys . 41 025203) argued that Purcell’s approach has a very limited validity and when it is applied in examples slightly different from those considered by Purcell it can lead to violations of basic tenets of electromagnetism, such as charge invariance and the principle of relativity. In this comment we dispute this conclusion by demonstrating that Purcell’s approach for an arbitrarily shaped current loop is equivalent to performing a Lorentz transformation and is thus valid as long as we relate fields in inertial frames. In addition, we examine some of D’Abramo’s examples.

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评论“关于赛尔磁力基本解释的注释”

在有关电磁学的开创性著作中，珀塞尔（Purcell）提出了一个概念上丰富的讨论，其中他使用洛伦兹收缩来关联从不同惯性框架观察时载流导线的电磁场。在最近的一篇论文中，D'Abramo（2020 Eur。J. Phys。41 025203）认为，赛尔方法的有效性非常有限，如果将其应用到与赛尔所考虑的示例稍有不同的示例中，则可能会导致违反赛尔的基本原则。电磁，例如电荷不变性和相对论。在此评论中，我们通过证明Purcell的任意形状电流回路的方法等效于执行Lorentz变换，从而对这一结论提出异议，因此只要我们将惯性框架中的磁场关联起来就有效。另外，我们研究了D'Abramo的一些例子。