Ern Switzerland, 1401 Yverdon-les-Bains, Switzerland; [email protected] electromagnetic Compatibility Laboratory, Swiss Federal Institute of Technology (EPFL), 1015 Lausanne, Switzerland Correspondence: [email protected]: Recent research function shows that you can find 4 procedures that can be utilized to calculate the electromagnetic fields from a present source. These distinctive procedures, even though generating the exact same total field, give rise to field components that differ from one process to one more. This has led for the understanding that the several field terms that constitute the total field can’t be uniquely determined. Within this paper, it truly is shown that all four field expressions might be reduced to a single field expression, and also the different field terms arising from acceleration, uniformly moving, and stationary charges is often uniquely determined. The variations inside the field terms arising from diverse techniques are brought on by the various strategies of summing up the contribution towards the total electric field coming in the accelerating, moving, and stationary charges.Citation: Cooray, V.; Cooray, G.; Rubinstein, M.; Rachidi, F. On the Apparent Non-Uniqueness on the Electromagnetic Field Elements of Return Strokes Revisited. Atmosphere 2021, 12, 1319. https://doi.org/ ten.3390/atmos12101319 Academic Editor: Sergey Pulinets o-Toluic acid web Received: 1 September 2021 Accepted: 3 October 2021 Published: 9 OctoberKeywords: dipole fields; radiation; induction; electrostatic; velocity fields; Coulomb fields; field elements; lightning; return stroke1. Introduction The students of electromagnetic theory are introduced, as a typical, to electromagnetic fields generated by an electric dipole once they are taught concerning the electromagnetic radiation [1]. It can be shown that the dipole electric fields may be separated into electrostatic, induction, and radiation terms, even though one particular can’t assign any clear physical significance to these field terms except for the radiation. An exciting question that a single can raise in this context would be the following: Are these field elements non-unique, or is there a different way to express the total fields in order that the physical processes that give rise towards the dipole fields develop into apparent A comparable problem exists in the case of calculating the electromagnetic fields of much more complicated sources, one example is, the return strokes in lightning flashes. In lightning study, return stroke models are utilized to estimate the electromagnetic fields at different distances generated by return strokes. These return stroke models specify the spatial and temporal variation from the charge and existing connected with the return stroke. Once this info is specified, it is actually feasible to calculate the electromagnetic fields making use of Maxwell’s equations (e.g., [2]). Nonetheless, as soon as the spatial emporal distributions of your return stroke charge and current are specified, there are several ways that the Maxwell’s equations can be utilized in calculating the electromagnetic fields. At present, you can find 4 solutions developed inside the literature to evaluate the electromagnetic fields when the spatial and temporal distribution of your current are given [8,9]. They are referred to as the dipole ((±)-Leucine Description Lorentz) approach, the continuity equation approach, and two versions from the procedures primarily based on moving and accelerating charges. All these procedures give rise to thePublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published m.