Obituary of George Jiri Linhart

George Jiri Linhart, fusion pioneer and author of one of the first textbooks on plasma physics, died in Frascati, Italy on 6 January 2011 at the end of a full life as an athlete, scientist, author and ocean sailor. He was 86 and had been in poor health for some time.

Jirka, as he was always known, was born on 13 April 1924 in Prague, Czechoslovakia and earned his Dipl. Ing. at the Prague Technische Hochschule in 1948. He was a member of the Czechoslovak swimming team at the 1948 London Olympics and took the opportunity to stay in the West, eventually becoming a naturalized British citizen. He joined the British Thomson-Houston Company in Rugby as a research physicist working on magnetrons, Cerenkov radiation and high temperature gas discharges. In 1953, while working at BTH, he obtained a PhD at King’s College, London. His thesis supervisor was Denis Gabor.

In 1956 he moved to CERN as a group leader in the Accelerator Research Division. There he worked on relativistic electron rings, plasma betatrons, plasma wave-guides and the theory of plasma. It was at this time that he wrote Plasma Physics (North Holland, 1960). It was the first textbook to describe the theory of the different approaches to fusion after the declassification of fusion research in the late nineteen-fifties. Plasma Physics was translated into Japanese, Chinese, and Polish; the third English edition was published in 1969.

His lifelong interest was the compression of plasma to high density and temperature by imploding liners. His early patents, filed while he was still at BTH, were concerned with using this method to obtain nuclear fusion. The idea was that expansion of the plasma would be tamped, and the confinement time increased, by the inertia of the liner, a process for which he coined the now-familiar term ‘inertial confinement.’

In 1960 he became head of the EURATOM group at the Laboratori Gas Ionizzati in Frascati, Italy. In collaboration with Heinz Knoepfel he set up a facility, MAFIN, to study the compression of magnetic flux by explosively-imploded metallic liners, eventually generating fields of up to 600 T. At the same time he and Charles Maisonnier studied the electromagnetic implosion of plasma liners in a hollow z-pinch called MIRAPI (MInimum RAdius PInch) and created, nondestructively, fields of over 100T on the axis of the pinch. This experiment was a forerunner of the giant z-pinch machines now being used to generate spectacular bursts of soft x-rays.

In 1972, when international enthusiasm for the tokamak began to displace alternative approaches to fusion, Jirka left Frascati and embarked on an enviably unconventional life, with various visiting professorships and sabbatical years at the University of Maryland, the University of Miami, and the Université de Paris-Orsay, France, separated by years of voyaging in his trimaran, Ianasha. He made two Atlantic crossings and was lucky to survive the second when his boat hit a whale. He spent some years living in the British Virgin Islands and represented the BVI at the Chess Olympics in Haifa in 1976. After returning to Europe he became Professor of Plasma Physics at the Università di Ferrara, Italy, an appointment which he held from 1985 and, emeritus, until his death. He re-acquired his Czech citizenship in 1990.

He continued to publish on the subject of high-density plasmas examining, among other things, the possibility of producing axial D-T detonation waves in a dense z-pinch. His final paper, Quo vadis fusion? (Nukleonika, 2009) was a lament for the present state of fusion research, where almost all resources are being consumed by the tokamak. He considered it unlikely that this approach would to lead to a commercial fusion reactor (a view shared by many others) and made a plea for the consideration of radically different ideas, offering his own work as an example.

Jirka’s interests were not confined to physics and his extensive list of scientific publications is punctuated with excursions into philosophy. He is the author of two monographs, The Galactic Society and On the Search for the Nature of God’s Justice (Melrose Press, 2004 and 2006, respectively) and reading these will remind his friends of their many wide-ranging conversations with him, often accompanied by good Italian wine. He will be remembered by his friends, colleagues and students as a man of many talents with a great zest for life.

He married Susanna Terrell in 1950. She and their five children survive him.