Power sources based on magnetic energy derived from superconductivity have been considered for commercial utility power, air and ground mobile power uses, and spacecraft applications . The advent of high temperature superconductors has reduced one of the penalties of superconducting magnetic energy storage in that the refrigeration and cryocontainers become greatly simplified. Still, structural and current density issues that limit the energy density and size of the superconducting inductors do not change. This paper covers basic principles of magnetic energy storage, structure requirements and limitations, configurations of inductors, attributes of high-Tc superconducting materials including thermal instabilities, a relative comparison with the state-of-the-art high energy density power sources, and refrigeration requirements. Based on these fundamental considerations, the design parameters of a micro superconducting magnetic energy unit for Air Force applications is presented and discussed.