RAYMOND C. MJOLSNESS April 22, 1933 – Sept. 13, 2023

We are deeply saddened to have lost Raymond C. Mjolsness on September 13, 2023. He was a fine theoretical physicist and applied mathematician, a patient mentor and insightful collaborator to colleagues, a longtime member of the Theoretical Division of the Los Alamos National Laboratory, and an excellent trombone player.

Raymond Mjolsness was born in Chicago on April 22, 1933. He grew up in several places including St. Louis, Missouri and Helena, Montana. He was an American original, a son of a school teacher who went on to excel in science and music. He was educated at Reed college, at Oxford under a Rhodes scholarship, and at Princeton. While at Oxford he studied trombone in London with Sidney Langston of the Royal Academy of Music.

While at Princeton he met his future wife Patricia, with whom he moved to Los Alamos and raised three children while working at the Laboratory and publishing dozens of scientific papers on plasma physics and related topics. His other interests included chess, finance, and running; also geopolitics and his Norwegian heritage. He owned and read an extensive and ever-growing collection of books, and was a regular customer at the Mesa Public Library.

Ray lived in Los Alamos from 1958 to 2014, with the exception of short forays into academia. From 1967-1969 he was on the faculty of Astronomy at Penn State, doing theoretical cosmology. He brought the family back to Los Alamos in 1969, just in time for the moon landing, moving into a house near the school on Barranca Mesa where he lived until 2014. He then moved to Enumclaw, Washington where he kept reading despite health challenges.

He is survived by his children Eric Mjolsness (Lora) of Irvine, California, Ingrid Kadrmas (Daryl) of Gladstone, North Dakota, and Kirsten VanderHoeven (Adrian) of Enumclaw, Washington, as well as grandchildren and great-grandchildren.