Charles Watson-Munro was trained as a scientist, majoring in chemistry and physics for his bachelor’s degree and primarily in geophysics for his master’s degree. After just two years working in physics and geophysics following graduation, he began work on the development of radar – a mix of physics and electrical engineering. That mix continued in the design and construction of the first nuclear reactors in Canada and the United Kingdom. The focus returned to physics for most of the last thirty years of his professional life when he moved first into cosmic ray research in New Zealand and then, after a short period as Chief Scientist of the Australian Atomic Energy Commission, into plasma physics at the University of Sydney. While the frequent shifts in fields of research made it difficult for Charles to develop as a major contributor in any one field, the resulting breadth of his expertise in science and engineering was a major factor in his success as a builder and leader of research teams. The other major factors in this success were his personal qualities – a sense of fun, integrity, loyalty to colleagues and students, concern for their welfare and development, and a desire and ability to get things done no matter how difficult the challenge.
The combination of scientific and engineering expertise and his personal qualities enabled Charles to make major contributions to science and engineering in four countries. In each country his contribution was at an early stage in the development of a particular technology – radar in New Zealand, nuclear power reactors in Canada and the United Kingdom, and nuclear science and technology in Australia. His contributions in New Zealand and Australia included participation in national committees and as a country representative on international committees.
Charles Norman Watson-Munro was born in Dunedin, New Zealand on 1 August 1915, the son of Machell Watson-Munro, an electrical engineer, and Ethel Watson-Munro (née Penny). He had two sisters. After a brief period in England from 1919-1921 the family returned to New Zealand, living first in Lyall Bay and then in Lower Hutt, where Charles received his primary and secondary school education. He was a reluctant secondary school student, at least initially. He would have much preferred to be apprenticed as a carpenter but his father thought that ‘wasn’t a gentleman’s education’. His interest in carpentry never waned and he made several pieces of furniture for his and his wife Yvette’s home in Sydney.
Charles matriculated in 1930 at the age of 15. He was always placed near the top of his class, although not quite so highly placed for conduct. One of his reports from secondary school carries the comment ‘With more care, could be higher in the class. Plays at work.’ Despite that play he was placed second in the class that year! The family was not affluent and whilst at secondary school Charles helped out by selling honey from door to door. Charles stayed on at school for a further year after matriculating to sit for the higher leaving certificate in order to qualify for a government grant to cover part of his university fees for a science course at Victoria University, Wellington. He worked part-time as a laboratory assistant and apprentice instrument maker while studying at university and completed his bachelor’s degree in 1935, first in his class in physics and chemistry. He stayed on at Victoria for postgraduate study, supported by a scholarship and graduated Master of Science with first class honours in 1937.
Towards the end of his university study Charles joined the Department of Scientific and Industrial Research (DSIR), working directly under the Head, Sir Ernest Marsden, who was to have a great influence on the early development of Charles’ career. Charles worked on a variety of problems in physics and geophysics during this period (1937-1939) in which he published his first scientific papers [12-14] . A fourth paper  , with Marsden as co-author, was published in 1944.
In 1939, at the start of the Second World War, Charles joined a team engaged in radar development. He was sent to MIT in 1941 where he spent almost a year gaining information on the design and use of the necessary microwave equipment. While in the United States, Charles also served as New Zealand Scientific Liaison Officer in Washington. On his return to New Zealand in 1942 he was appointed Director of the Radar Development Laboratory, which grew to have a staff of 150. Charles’ visit to MIT had been so profitable, and his leadership skills already so well developed, that the Laboratory was able to sell around 15-20 sets to the United States for use in the Pacific war zone. In 1944, with the rank of Major, he took part in amphibious operations with US marines at Bougainville using the New Zealand radar equipment. He was made an Officer in the Order of the British Empire (OBE) in 1946 for his radar work during the war.
Shortly after returning to New Zealand from MIT Charles met Mark Oliphant who was visiting New Zealand to assist in the work on radar. The two had numerous contacts after that initial meeting. Charles believed that Oliphant, with Marsden, was influential in having Charles included in the group of New Zealanders who went to Chalk River (see following section).
In 1944 Charles and several other New Zealand scientists were invited go to Chalk River, Canada, to join a team of Canadian, UK and European scientists undertaking research on the peaceful uses of nuclear energy. The research was largely devoted to heavy water types of reactors that would subsequently be the basis of the highly successful Canadian nuclear reactor industry. Charles’ main task at Chalk River was the design of the control equipment for the heavy water reactor ZEEP (Zero Energy Experimental Pile), the first reactor to be built outside the United States. While in Canada Charles met his wife-to-be, Yvette Diamond, at a ski lodge in the Laurentian Mountains.
Early in 1946 a joint UK-New Zealand team, including Charles, commenced work at the newly founded Atomic Energy Research Establishment at Harwell, England, on the design and construction of two graphite moderated natural uranium reactors – BEPO (British Experimental Pile-0) and GLEEP (Graphite Low Energy Pile). The plan was to build GLEEP, a simplified version of BEPO, to check out the reactor physics for the design of BEPO and to provide radiation facilities for the Harwell site. Charles was given the responsibility of leading the GLEEP team. Construction began in August 1946 and the reactor went critical on Friday 15 August 1947. The short construction time, in the very difficult conditions that prevailed in England immediately after the end of World War II, was a remarkable achievement and owed much to Charles’ skills as a scientist, engineer, and team leader.
On the occasion of the thirtieth anniversary of the commissioning of GLEEP D J Taylor, the then GLEEP and DIDO Reactor Manager, remarked 
GLEEP has long outlived its immediate successor, BEPO, which closed down in 1968 after twenty year’s operation, and can claim to be the progenitor of all the British graphite reactors. GLEEP’s unique record of service, stability and safety is a tribute to those who designed, built and commissioned it thirty years ago.
GLEEP continued in operation until September 1990.
James Stewart, Charles’ deputy at Harwell, comments  ‘He was an outstanding project leader; a man of enthusiasm, commitment and drive, but at times a little impatient.’ and ‘Such a project is a fitting tribute to Charles Watson-Munro’.
Charles returned to New Zealand in 1948 to take up appointment as Deputy Head of DSIR where he had responsibility for directing research in physics, geophysics and engineering. Although Charles was not personally involved in much of the research, he had a major role in ensuring that it was of high quality and in fields of particular relevance to New Zealand including aerial magnetic surveys, geothermal energy, carbon dating, and meteorological studies based on measurements of the radioactivity of air.
In 1951 Charles resigned from DSIR to accept appointment as Professor of Physics at Victoria University, Wellington, where he carried out research on cosmic rays. With only relatively rudimentary equipment, his research group’s output was small, but it did include an interesting paper on the detection of radioactive dust from the British nuclear bomb tests of October 1953 which showed that the dust had been transported very rapidly from the bomb site to Wellington by the very high velocity, high altitude winds prevailing at that time. 
In 1955 Charles took up appointment as Chief Scientist with the Australian Atomic Energy Commission (AAEC). The Commission had been established under the Atomic Energy Act 1953 with a wide range of functions and powers. In the first few years, the AAEC focused its attention on the development of an Australian uranium mining industry and on the initiation of a research and development program. The latter had, as one of its main objectives, the development of a joint R&D program with the United Kingdom (which had already undertaken a vast amount of work on reactor design and on the peaceful applications of nuclear energy, particularly its use in electricity generation). Shortly after his appointment, Charles joined the group of Commission staff working at Harwell on the joint program. He returned to Australia in 1957 to take direct charge of the research program and to oversee the completion of the initial set of buildings at the research establishment at Lucas Heights, a Southern suburb of Sydney, and the final stages of construction of the research reactor, HIFAR (High Flux Australian Reactor). The reactor, which was essentially the same design as the UK reactor, DIDO, went critical on Australia Day, Sunday, 26 January 1958. It has proved to be a remarkably successful research tool and also an important source of radioisotopes for use in industry, medical diagnostics and the environment.
The Commission’s original intention was to locate the reactor at Maroubra, a densely populated seaside suburb in Sydney. Charles was influential, with the assistance of Oliphant and others, in having the site moved to Lucas Heights which, at that time, was an outlying suburb with the nearest housing ‘about one and a quarter mile away’  from the reactor site.
The principal objective  of the research program in those early days was ‘the development of the means for the economic production of industrial electric power from nuclear fuels’. 
This was the challenge that attracted Charles to the AAEC; at that time, Australia’s vast coal resources were not widely known. It soon became clear to him that the likelihood of Australia developing a nuclear power industry was remote and, in 1960, he accepted appointment as Professor of Physics (Thermonuclear) at the University of Sydney.
Charles was the ideal man for the job of AAEC Chief Scientist. With the commissioning of HIFAR he became perhaps the only person to be involved in the design, construction and commissioning of the first nuclear reactors in three countries – Canada, the United Kingdom, and Australia. His appointments in those three cases, and the highly successful outcomes, are a testimony to his scientific and technological ability and to his extraordinarily high administrative and management ability.
Two of the leading AAEC staff appointed in the period leading up to the commencement of operations at Lucas Heights were Keith Alder and Grant Miles. Their comments  on the early days there and particularly on Charles’ role as Chief Scientist include the following:
Charles could be informal and facetious – indeed, some of the team who had been a long time in the UK and were accustomed to English attitudes found his approach sometimes embarrassing. This was accentuated by his smoking habits – a well-chewed cigar or cigarette that, when deep in discussion, he was liable to light at the wrong end.
Charles’ informality and willingness to listen quickly gained him the confidence of the Australian group. His involvement in the very early days of atomic energy, both in Canada and the UK, was most important in Australia’s liaison with the UK and other countries.
He was also an excellent chairman of meetings, able to keep them crisp, short, and effective – with low tolerance for irrelevance; and he was a good lecturer.
Charles came to the AAEC equipped with a broad knowledge of physics, and while by temperament an experimentalist, he placed great store on ‘solid’ scientific training and achievement. He always sought and encouraged the ‘first class’ and established a tradition in recruitment and the merit assessment and promotion of staff, which provided a firm basis for the subsequent evolution of the Research Establishment.
Soon after taking up appointment at Sydney, Charles realised that the description ‘Thermonuclear’ might conjure up unpleasant images among the general public and so he sought, and received approval, for the change to Plasma Physics in the title of his chair. The change in title didn’t reflect any change in objective: that remained to undertake research into the possibility of using nuclear fusion reactions in the generation of electricity – a possibility that Charles had become aware of when he attended the second ‘Atoms for Peace’ conference in Geneva in 1958.
Charles set about with great enthusiasm and energy building up his research group (‘Department’ in the terminology adopted by Professor Harry Messel to describe the research groups in the multi-professorial School of Physics that he headed). The W. D. and H. O. Wills Plasma Physics Department (the full title reflecting the generous gift from the company to assist in its establishment) was one of five departments, each with a professorial head, established by Messel in the late fifties. In each case, Messel had secured private funding from an individual or company to support the research – a remarkable and still unique achievement for an Australian university.
Messel readily agreed to Charles spending a year at the University of California, Berkeley, to familiarise himself with some of the science and technology of the field. He returned from Berkeley at the end of 1960 and I joined him early the following year as his first non-professorial staff member, having switched into plasma physics from nuclear physics at Princeton University during 1960 in preparation for taking up my appointment in Sydney. Charles had decided to use a method of plasma preparation for the Sydney experiments that had begun to be studied at Berkeley. During discussions at Princeton, he and I were able to target the key technologies that would be needed to ensure the successful implementation of that plan – a tactic similar to that used in the AAEC research program.
The plasma preparation method chosen for Sydney was hydromagnetic ionising fronts – a highly non-linear phenomenon that had the double advantage of producing a highly ionised plasma at relatively low cost and of providing an interesting and complex subject for research in its own right. Charles described the approach in the first two published papers from the group. [29, 30] Over the next two decades, a succession of linear plasma sources – the SUPPER machines  (Sydney University Plasma Physics Experimental Rigs) – were constructed using this method of plasma preparation. Although the temperatures obtained in the SUPPER machines were low compared with those obtained in larger (and more expensive) devices overseas, the plasma conditions were adequate for significant contributions to be made by the group to fusion related plasma problems, particularly in the study of both linear and non-linear characteristics of Alfven waves and in the development of techniques for plasma diagnostics (the measurement of plasma parameters such as density and temperature).
The second plasma device constructed by the group, SUPPER II, was constructed to study a method of plasma heating known as ion cyclotron heating. For this purpose, a 1MW, 8.5 MHz pulsed oscillator was constructed, but it did not produce the desired heating of the plasma. Consequently, Charles decided that more basic studies of wave propagation in the plasma would be necessary to understand the nature of the problems encountered with the heating experiment. This involved a large number of experiments on Alfven waves, including both the fast (compressional) and slow (torsional) wave types, at frequencies from about 1 MHz up to and above the ion cyclotron frequency.
The Alfven wave experiments were extended in the late sixties to include large amplitude waves, driven by alternating currents of up to 200 kA in the plasma. It was quickly discovered that at such large amplitudes, the waves became shock waves, with the potential for significant plasma heating. An extensive series of experiments were conducted up to about 1975 on ionising shock waves propagating into an upstream neutral gas in the presence of strong magnetic fields, as well as the so-called MHD switch-on shock waves that propagated into an upstream plasma. During this period the work on shock waves was done in close collaboration with the group led by Prof Bob Gross at Columbia University. Charles worked closely on the Alfven and shock wave experiments with his PhD students, including Ian Brown, Rod Cross,  Brian James,  Rory Niland, Frank Paoloni, and Lee Bighel.
The large volumes of plasma produced by the ionising shock waves were useful for the development of plasma diagnostics. Initial emphasis was on spectroscopy and microwave interferometry, but this was soon followed by the use of lasers for interferometry and Thomson scattering. The work on diagnostic development grew to become one of the major activities of the Plasma Physics Department.
A series of journal articles and conference papers resulted from this work. [29-61, 65, 67, 68] Charles was awarded a DSc in 1968 by Victoria University, Wellington, after submitting 23 of these publications for examination.
The work on hydromagnetic ionising fronts and on large amplitude Alfven waves was pioneering and highly relevant to the important issues of plasma preparation and heating. It was only matched in quality and timing by parallel studies in major laboratories in Russia. The work, and Charles’ ability as a communicator at international conferences, established the Sydney group as an important, although small, contributor to the international fusion research effort. This contribution, together with those of groups at the Australian National University and at Flinders University, enabled Australia to stay in touch with developments overseas. The work on small amplitude Alfven waves also attracted international attention and was the foundation for later work in the toroidal geometry of the Sydney tokamak, TORTUS, which was commissioned shortly after Charles retired.
A measure of the standing of the group, and of Charles in particular, is that he was chosen as one of only four people to present invited papers on the state of controlled thermonuclear research worldwide at the Third Atoms for Peace Conference in Geneva.  The other three papers were presented by researchers from Russia, Germany and the United States. The group was also well known for the very high quality of its graduates, the majority of whom went overseas for postdoctoral experience, in most cases to major laboratories where they were highly regarded.
Towards the end of his career Charles developed an interest in other energy sources, particularly solar energy. [62-64, 66, 69] He was the prime mover behind the successful work on solar energy that led to the formation of the Department of Applied Physics within the School of Physics. His involvement with solar energy research and with broader aspects of energy research continued for a few years after his retirement through his appointment as Energy Consultant to the Science Foundation for Physics at the University from 1981-1985.
Charles had exceptional administrative and leadership qualities. Stewart’s comments on his time at Harwell have already been referred to.  He was ‘without peer as a committee member’.  These qualities were obvious very early in his career; he was just 27 when appointed Director of the New Zealand Radar Development Laboratory and only 30 when given the job of leading the team that designed and constructed the first nuclear reactor in the UK. In 1964, Sir Mark Oliphant commented, 
I know Watson-Munro to be a first class physicist and engineering physicist. He displays enormous energy and enthusiasm for whatever he is doing and always makes significant contributions to the subjects he tackles. His greatest asset is his ability to make things work, however complex equipment or experiment may be.
These administrative and leadership qualities, and his great breadth of experience and scientific knowledge, enabled Charles to make many significant contributions to Australian and international science through service on numerous committees and advisory bodies, on many of which he served a term as chairman. These bodies included the UN Committee for the Establishment of the International Atomic Energy Agency (1955); the International Fusion Research Council (1968-1980); the UN Scientific Committee on the Effects of Atomic Radiation (1973-1974); the Australian Institute of Nuclear Science and Engineering (1958-1980); the Australian Research Grants Committee (1969-1973); the Queen Elizabeth II Scholarship Committee (1974-1979); the Australian Ionising Radiation Committee (1974-1978); the National Energy Advisory Committee (1977-1979); and the National Energy Research, Development and Demonstration Council (1978-1981).
Charles’ abilities as an administrator and leader were founded on a wonderful personality – full of humour; a well developed sense of mischief with an accompanying impish twinkle in his eyes; a healthy disdain for bureaucracy, particularly that located in Canberra; until quite late in life, treatment of a cigar that was more chomping than smoking;  and a legendary concern for, and loyalty to, his staff and students. Yvette, his wife, supported Charles wonderfully in his career; together, they hosted many social gatherings at their home. In the 60s and 70s these gatherings played an important part in developing a common sense of purpose for the plasma physics group.
Charles’ health deteriorated markedly following the death of Yvette in 1989. He died peacefully in hospital in Melbourne on 10 August 1991. He is survived by his son, Tim. He is greatly missed by Tim and his many colleagues and friends.
This memoir was originally published in Historical Records of Australian Science, vol.14, no.1, 2002. It was written by M.H. Brennan, who lives in Netherby, South Australia.
Reminiscences and comments from many of Charles’ colleagues and friends have been a great help in preparing this memoir. These are annotated in the text. Two other sources of material were conversations between Charles and the author and a transcript of an interview conducted with Charles in March 1991 by Jane Innes.  Material drawn from these latter two sources is generally not annotated. The photograph, taken ca 1966, was submitted by Charles for the Academy’s archives.
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