Potential Interpretation of the Meissner Effect in Superconductors: Insights from Vector Magnetic Circuit Theory

A superconductor placed in a weak magnetic field and cooled down through the transition temperature expels magnetic flux. This phenomenon, known as the Meissner effect, is arguably the most essential property of superconductors. Although macro phenomenological theories and micro theory of superconductors are available, there is still lack of simple and clear clarification of the mechanism of Meissner Effect from macro electromagnetic perspective by now. In this study, a vector magnetic circuit theory is proposed to scrutinize the limitations of the classical electromagnetism theory. A thorough analysis is conducted to elucidate the underlying mechanisms governing the Meissner effect in superconductors with the application of vector magnetic circuit theory and time-varying magductance, as well as to discern the distribution of screening currents of the superconducting. The utilization of the vector magnetic circuit theory facilitates the successful differentiation between the perfect conductor and the superconductor under field-cooled condition. Finally, a closed superconducting coil experimental platform is constructed to validate the effectiveness and feasibility of the proposed theory. This experimental support is of paramount importance for theoretical research and engineering applications of superconductors, and provides a reliable foundation for future investigations into the magnetic circuit behavior and magnetic circuit characteristics specific to superconducting materials.