Michael Kaufmann came to the IPP in 1965 and spent almost his entire scientific career there. In 1978 he was appointed Director at the IPP and Scientific Member of the Max Planck Society. He was a member of the Board of Directors from April 1981 to March 1993 and again from July 2000 until his retirement in March 2007. Since 1990 he has also been an honorary professor at the University of Bayreuth.
Michael Kaufmann played a major role in the development of fusion research: At the beginning of his scientific career, he initially focused on investigations of the z-pinch, theta-pinch and high-beta stellarator. The achieved physics understanding of the plasma processes in these early devices was incorporated into the work on the more promising competitor, the low-beta line - tokamak and stellarator. After a brief interim phase in the planning of an ignition experiment (ZEPHYR), which was ultimately not realized, in 1981 he took over as head of the planning group for ASDEX Upgrade, the new tokamak experiment of IPP, and successor to the successful ASDEX. Ten years later, the facility started scientific operation in the department Experimental Plasma Physics 1, headed by him.
One of his ideas from the ZEPHYR era, a 'photosphere' at the edge of the plasma that gently radiates energy, led to the demonstration of the Completely Detached H-Mode at ASDEX Upgrade in 1993: externally supplied neon radiates energy at the edge, and the plasma practically detaches from the divertor plates.
Like almost all tokamaks in the early 1990s, ASDEX Upgrade used carbon as a wall material. Knowing that carbon would never become a material for a reactor wall, in 1996, under Michael Kaufmann's leadership, IPP began to coat first the divertor and then the entire wall of the plasma vessel with tungsten. This was done despite bad experiences with tungsten in other laboratories and against some well-meant advice. The key to success was the cold plasma edge at ASDEX Upgrade. In 2007, the year of Michael Kaufmann's retirement, the last carbon tile was replaced with tungsten. A direct consequence of these developments was the subsequent replacement of the JET divertor by a tungsten divertor and the decision to abandon the planned ITER operation with a carbon divertor.
Michael Kaufmann was not only an outstanding scientist, but also an equally successful science manager. IPP Director Sibylle Guenter said "It is to him that IPP owes not only many suggestions for project management and the safety culture at IPP, but also a significantly improved integration of the IPP into the German and European research landscape".
Michael Kaufmann made great efforts to integrate countries that were not so experienced at the time, such as Greece, Ireland and Portugal, into fusion research. "With the Europeanization of the ASDEX Upgrade programme via its programme committee, he implemented the joint use of the European fusion facilities, which is now taken for granted," Prof. Guenter said.
As a committed university lecturer in Bayreuth, but also in contact with many other universities, Prof. Kaufmann successfully worked to ensure that fusion research has become part of physics education at many universities. His textbook 'Plasma Physics and Fusion Research’, was published in 2003 and he continued to work on updating it after his retirement.
Prof. Guenter states, "Many employees of IPP, including several later members of the board of directors, benefited from the support of Michael Kaufmann. In the promotion of young scientists, he succeeded like hardly anyone else in combining support and demand in an outstanding way. He demanded a lot from his employees, but he also took meticulous care to ensure that the employees always received the full credit for their work, and in this way he promoted many careers".
All fusion research in Germany and the fusion world owes Michael Kaufmann much and will remember him with honor and gratitude.
Friends and colleagues of Michael Kaufman may send thoughts and
Prof. Dr. Sibylle Günter
Max-Planck Institute for Plasma Physics Garching/Greifswald