Bo Lehnert 1926-2025

Professor Emeritus Bo Lehnert has passed away at the age of 99. He is survived by his wife, Ann-Marie, as well as by family, friends, and colleagues. Bo Lehnert was an internationally recognized pioneer in controlled nuclear fusion research and made significant contributions both as a scientist and as a leader. He was also a very well-liked and cheerful person.

Bo was born in Stockholm and earned his doctoral degree at KTH in 1955 under the supervision of Hannes Alfvén. Already as a doctoral student, he contributed to research in magnetohydrodynamics and plasma physics, fields that would become central to his lifelong work in fusion. Under his leadership, research at KTH expanded both theoretically and experimentally, and he played a key role in establishing international collaborations, including within the European Euratom framework.

Bo Lehnert received several prestigious awards and was a member of multiple academies of science. He was admired for his sharp analytical mind, his generosity, and his warm and friendly manner. His colleagues remember him with great affection, and he will be deeply missed.

In the autumn of 2026, the Division of Electromagnetics and Plasma Physics will name meeting room 5406 in honor of Bo Lehnert.