Obituary: Professor Tom Kaiser

TOM KAISER was Professor of Space Physics at Sheffield University from 1966 until 1987. During this period he attracted high-quality scientists to Sheffield, building up an internationally renowned group in Space Geophysics.

His move to Sheffield occurred at an important time. The space age was about to begin, and he was one of the first to recognise that space technology would be important for the study of the upper atmosphere. He built up experimental expertise at Sheffield in radio frequency (RF) impedance probes to fly on rockets and was Principal Investigator for similar experiments flown on the early UK satellites, Ariel 3 and Ariel 4. Ariel 4 measured very low frequency radiation that arises from disturbances due to the entry of charged particles into the ionosphere, from thunderstorms and man-made sources.

Kaiser also recognised the benefits of making simultaneous measurements from the ground and was heavily involved in the development of the very low frequency (VLF) programme at the British Antarctic Survey at Halley Bay. He was foremost among UK scientists in realising the potential of Antarctica for space physics research. The space and ground-based programmes also led to Kaiser's interest in wave-particle interactions in space plasmas.

Kaiser had come to England from Australia in 1947, having obtained first class honours in his Bachelor's degree in Physics at the University of Melbourne in 1943, followed by a Master's in 1946 while working as a research officer in the Sydney Radiophysics Laboratory of the Council for Scientific and Industrial Research.

On arriving in England he went to University College and the Clarendon Laboratory, Oxford, completing his doctorate, on the acceleration of charged particles, in two years.

Because of the Cold War political climate at the time, Kaiser was forced to return to Australia as a result of an incident that became known as "the Kaiser affair", in which he took part in a demonstration outside Australia House against the Australian government's gaoling of union leaders during a coal strike. However, as a member of the Communist Party, Kaiser's continued political activity made it necessary for him to leave Australia for good in 1950. He joined Manchester University's Jodrell Bank Experimental Station as the Turner Newell and ICI Research Fellow.

In the early days of radio astronomy at Jodrell Bank, Kaiser was fascinated by the train of ionised atoms that an incoming particle of interplanetary dust leaves behind as it burns up in the atmosphere and the way in which this train can be quantified by looking at the radar signals reflected from it.

He carried out theoretical and experimental research on the ionisation trails of meteors, using the then relatively new scientific technique of radar. This pioneering work provided the scientific basis for a number of different research fields, in particular the development of meteor radar reflection as a diagnostic for the study of winds in the upper atmosphere. His early papers on the cross-section of the meteor ionisation trail are still regarded as the fundamental ones in this area.

Tom Kaiser was always concerned to help, and support fearlessly, the under-privileged and those he thought might have been wronged. I believe he enjoyed pulling the tails of those in high authority, especially if he judged them to be pompous and incompetent.

He was an inspirational teacher and motivator of both undergraduate and graduate students. Many happy hours were spent at the hilltop site near Sheffield that he covered with a variety of radar aerials. Even on cold and wet nights, his stories kept you going and the happy marriage between theory and experiment and the feeling that science is fun was consolidated.

Thomas Reeve Kaiser, space physicist: born Melbourne, Australia 2 May 1924; Turner Newell and ICI Research Fellow, Jodrell Bank Experimental Station, Manchester University 1950-55; Lecturer in Physics, Reading University 1955-56; Senior Lecturer in Physics, Sheffield University 1956-66, Professor of Space Physics 1966-87 (Emeritus); married 1949 Pamela Pound (two sons, one daughter); died Palma, Majorca 2 July 1998.