Semantics of HTS AC Loss Modeling: Theories, Models, and Experiments

Computer-assisted modeling is an essential approach to design new devices. It speeds up the process from the initial idea to an actual device and saves resources by reducing the number of built prototypes. This is also a significant practical motivator behind scientific research in contemporary high-temperature superconductor (HTS) ac loss modeling. However, in the scientific literature in this field, consistent practices about modeling terminology have not been established. Then, it is up to the reader to decide, what is the true intent and meaning of the authors. Consequently, the interpretation of such literature might be very much reader dependent. An inseparable part of the whole modeling process is the development of modeling approaches and numerical methods and comparing the predictions obtained via modeling to experimentally achieved results. It is commonplace to discuss the accuracy of modeling results or the validation of a model. In this article, we discuss the terminology related to theories, models, and experiments in the context of HTS ac loss modeling. We discuss the recursive nature of theories and models in this context, discuss the compatibility of discrete formulations of physics utilized in our field with the corresponding continuum description, and interpret the perceived meaning of validation of a self-consistent model, shedding light on the relationships between theories, models, and measurements. We present our view on understanding these relations in the familiar context of ac losses in HTS, studying case examples through simulations and literature. As a result, we end this article with four conjectures describing our views.