Vector potential formulation of a quasi-static EM induction problem: existence, uniqueness and stability of the weak solution

We deal with the electromagnetic induction in a conductor with 3D distribution of electric conductivity in quasi-static approximation with the focus on theoretical aspects related to the solvability of this problem. We formulate the initial, boundary-value problem of electromagnetic induction in terms of a magnetic vector potential only, first in differential and then in integral forms. We prove that the problem is well posed in the Hadamard sense, that a solution exists, is unique and continuously dependent on data. The fact that no electric scalar potential is employed in the formulation and no gauge condition is imposed on the magnetic vector potential makes the formulation attractive for numerical implementations.