Scoping magnetic fields out for prevention (Vol. 49 No.5-6)

Magnetic field generated by a current (I) through a finite wire

A new study reveals how to best evaluate the circulation of magnetic fields around closed loops

Concerns about the effects of magnetic fields on human health require careful monitoring of our exposure to them. Mandatory exposure limits have been defined for electric and hybrid vehicle architectures, in domestic and work environments, or simply to shelter sensitive devices from unintended sources of magnetic disturbance. In a new study published recently, the authors develop a method for deriving an approximate value of the circulation around a loop of the magnetic field generated by the flow of electric current in an arbitrarily-shaped wire of a given length. In this study, the authors set out to adapt Biot-Savart’s law, which describes the magnetic field generated by finite wires, to evaluate the circulation of such fields around a closed path or loop. This led the authors to a mathematical formula that, as the finite wire thickness decreases to zero, becomes identical to one of their recent research results expressing the magnetic field circulation as a function of the wire current and of the solid angles between the circulation path and each of the conducting wire’s endpoints.

J. M. Ferreira and J. Anacleto, The magnetic field circulation counterpart to Biot-Savart’s law, Eur. Phys. J. Plus 133, 234 (2018)