Converging on the Vortex: James Tuck, James McDonald, and the Independent Pursuit of Anomalous Atmospheric Phenomena, 1967–1971

This document reconstructs the parallel and apparently independent trajectories by which two physicists of the first rank — James L. Tuck (Los Alamos National Laboratory, founder of Project Sherwood) and James E. McDonald (University of Arizona, Institute of Atmospheric Physics) — arrived at the same research object between 1967 and 1971: the stable atmospheric vortex ring documented at Fort Belvoir, Virginia. Tuck arrived through plasma confinement physics. As the founder of Project Sherwood and the leading U.S. expert on rotating magnetohydrodynamic structures, he recognized in the Fort Belvoir vortex a macroscopic atmospheric analog of the confinement problems he had spent his career investigating. His December 1970 letter to the Army Engineering School — requesting the experimental protocol for producing "large atmospheric vortices" — was the formal expression of that recognition. McDonald arrived through atmospheric physics and UAP case investigation. By early 1971 he was planning a formal NSF research proposal on vortex ring physics. He died in June 1971. The proposal was never submitted. The convergence is documented from verified primary and secondary sources. No direct communication between the two men has been established. All claims are drawn from verified sources; no unverified connections are asserted. This document is part of a five-document series. Companion documents: minimum experiment (Doc1), full technical proposal (Doc2), plain language summary (Doc3), and historical analysis of the Tuck letter (Doc4) available in the same Zenodo repository.