Obituary of W. James Carr Jr.

Walter James (“Jim”) Carr, Jr. – versatile and creative theorist, engineer, and inventor in fields ranging from the physics of magnetism and magnetic materials to ac loss theory in superconducting composites and its practical application to the design of large-scale superconducting apparatus – died at home in Pittsburgh, Pennsylvania, on November 16, 2010, at age 92. Jim was a Fellow of the American Physical Society and the IEEE. Jim was born on May 6, 1918 in Knob Noster, Missouri. Intending to study journalism, he switched to engineering after receiving a full-tuition scholarship to the Missouri School of Mines and Metallurgy (later University of Missouri-Rolla, now Missouri University of Science and Technology). He graduated in 1940 with a BS in electrical engineering. He then entered Stanford University, where he studied under Frederick Terman and graduated in 1942 with an MS in electrical engineering. Upon graduation, he was recruited by the Westinghouse Research Laboratories (later the R&D Center) in Pittsburgh, PA, to join the wartime effort on defense projects. After the war, he wanted to study physics to know the “why” behind the engineering. Westinghouse initially declined to grant him leave citing his value to the lab, but eventually sponsored his graduate studies at Carnegie Tech (now Carnegie-Mellon University), where he conducted research in magnetostriction under Roman Smoluchowski and earned a DSc in physics in 1951.

Jim retired at age 67 after 43 years at the Westinghouse R&D Center with a six-month sabbatical at the Atomic Energy Research Establishment in Harwell, U.K. He retired as a Consulting Scientist, the highest non-managerial rank and a rare distinction in that organization. By the late 1960’s he had also come to direct a group of theorists, but later mainly created his own projects, consulted, and mentored younger scientists. He continued consulting for Westinghouse and other organizations and remained professionally active until the last years of his life. A W. James Carr, Jr. Memorial Lecture series has been established at the Department of Physics, University of Maryland, in his honor.

Jim was elevated to Fellow of the American Physical Society and to IEEE Fellow for his contributions to theories of magnetism and for development of the theory of ac losses in composite superconductors. In the early 1970’s, he was also active in an informal association called “Pittsburgh Magneticians”, which he co-founded to discuss papers and new issues in magnetism and magnetics. This organization also helped some immigrant Jewish magneticians from the former Soviet Union to integrate professionally.

Jim coupled a strong capability in mathematics with a deep and intuitive understanding of physics. He had a penchant for starting from first principles, but he also had an eye for the practical and worked equally well with theorists and design engineers. Until about 1970, magnetostriction and anisotropy of iron and alloys continued to be his interest as documented by many publications, while he also significantly contributed to the understanding of direct exchange in two and many-electron systems in the 1960’s, finally suggesting (Phys. Rev. 1986) superconducting behavior in solid hydrogen based on direct electron-phonon coupling. In the 1960’s he also supported theoretically an extensive experimental investigation of magnetic and superconducting tellurides (especially the SnTe-MnTe system) and derived a macroscopic theory of superconductivity in the framework generally used for magnetic materials, one that he considered important for the development of thermodynamics related to type-II superconductors (Phys. Rev. 1981).

In the early 1970’s, Jim developed “The Anisotropic Continuum Model”, an elegantly derived theory of ac losses in twisted multifilament composite superconductors that facilitated practical tradeoffs in the design of large scale superconducting devices ranging from high energy physics accelerators to generators, motors, transformers, transmission lines and fusion reactors ^[1] . This forged an ongoing collaboration between Jim and a community of developers within and beyond Westinghouse that lasted the rest of his life. He received 13 patents in his lifetime from metallic weapons detectors to superconducting devices.

After the new high-Tc superconductors were discovered early in the 1990’s, Jim began to address ac losses for the coated tape geometry, working with others to devise transposed striated forms and, starting in about 2000, finding conduction and hysteresis losses to involve a surface charge distribution. These ideas are incorporated in his last paper, “Basic Theory of an All-Superconducting Generator” (IEEE Trans. Appl. Supercond., 2007).

Those of us who knew and worked with Jim admired his sharp and creative mind, his impeccably logical reasoning and his fine way of working with people. We will very much miss this most courteous and gentle colleague and friend.