[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - The Role of the Magnetic Constant, j.10, in the Redefinition of the SI

摘要： This paper explores the origins of the ‘magnetic constant’, μ0, within the present SI, and its role in the imminent redefinition. An attention to the history and meaning of this constant helps to clarify the structure of our unit system, and reveals the extent to which practical unit choices in electricity influence the way we write the fundamental equations of physics. A concern is raised about the use of the name ‘vacuum magnetic permeability’, as this suggests a physical meaning that is not justified. The potential for misinterpretation will increase when μ0 becomes experimentally determined in the revised SI.