Fields from a uniform current source: Instantaneous switch‐on

摘要

Electromagnetic fields from switching on and off a constant current distributed over a plate of finite extent are studied. Such current distribution will set up a magnetostatic field and an electric dipole field behind the initial transient pulse. Over an area equal to that of the plate, there is a finite volume in which the strengths of theEandHfields of the transient pulse do not decrease with distance. This finite volume decreases as the inverse of the distance from the source so that the energy contained in this volume also decreases as the inverse of the distance traveled.