Annual report 2006
The National Plasma Fusion Research Facility was established by the Australian National University (ANU) and the Commonwealth of Australia through the Major National Research Facilities (MNRF) Programme. Funding was initially over the period 1997-2005 with an extension under existing funding until 2010. 2006 was the first full year under the new arrangements for the Operational Phase and marked the completion of the transition from parallel efforts of construction, commissioning and operation to a more efficient, largely automated mode of operation in support of research. The Commonwealth MNRF funding of $8.7 million, building on the H-1 Heliac plasma confinement device, provided upgrades of the power supplies for plasma heating and magnetic field, control and data acquisition systems, advanced plasma measurement systems and other infrastructure, bringing the total value of the facility to in excess of $20 million.
The mission of the Facility is to perform basic research into high-temperature plasma as part of an international program, whose ultimate aim is ecologically sustainable power generation by the controlled fusion of hydrogen isotopes. Important outcomes are development of plasma measurement systems, and technological spin-offs. The Facility has met the majority of its milestones, and exceeded expectations in the area of remote control and technology development.
This year many improvements were made to the Facility, including a substantial upgrade of the data system to a linux/MDSplus open source system, increasing speed by more than ten times, the construction of a new interchangeable foil soft X-ray detector, and the commissioning of a fast electronically scanning interferometer for measuring electron density profiles and their time evolution. The recently installed supersonic helium beam diagnostic for measurement of temporally and spatially resolved electron temperature and density came into full operation, in collaboration with the University of Sydney, and the fast electron beam mapping system has successfully mapped magnetic fields at the full operational magnetic field of 0.5 Tesla.
H-1NF provides an important resource to a wide range of researchers, national and international, world-class training to graduate students, and has generated a broad range of spin-offs for manufacturing, defence and communications industries. The extensive scope of these fundamental and technological challenges also equips the group to engage in a diverse range of related and complementary pursuits, which are summarised below in conjunction with the core plasma research from which they are derived.
In 2006 the Turbulence and Transport Studies Group led by Dr Michael Shats expanded the scope of their research; studies into the interaction between large coherent structures and turbulence in plasma were complemented with experiments in quasi-two-dimensional fluid turbulence. Among new important results was the discovery of the role of mean zonal flows in the formation of transport barriers in the improved confinement mode. The formation of zonal flow coincides with suppression of turbulence near the transport barrier. This confirms that spectral condensation previously suggested by the group as the universal mechanism of plasma self-organization, is indeed an important ingredient in the physics of improved plasma confinement. These results were published in Physical Review Letters. Hua Xia was awarded a PhD degree in 2006 and was appointed as a Postdoctoral Fellow with the group. The group had a central role in organizing 19th Canberra International Physics Summer School held at ANU in January 2006 (convenor Dr M.G. Shats) and the Workshop on Turbulence and Coherent Structures in Fluids, Plasma and Granular Flows. Drs M. Shats and H. Punzmann have compiled and edited a book of Lecture Notes published by World Scientific as part of the Lecture Notes in Complex Systems series. The book includes a chapter ‘Experimental studies of plasma turbulence’ by M.G. Shats and H. Xia.
The Advanced Imaging and Inverse Methods Group led by Professor John Howard undertakes research into passive (optical) and active (laser-based) techniques for plasma diagnostics, and their associated inverse methods, with applications in industry and medicine. This year saw a number of invited international talks on our patented optical coherence imaging (CI) technologies. Under contract to the Japanese Atomic Energy Agency, we have developed and successfully operated a compact CI system for Thomson scattering, and in addition have deployed a system for imaging of high temperature molten iron flows at Bluescope Steel. Supported by an Australian Research Council (ARC) Discovery Grant and in collaboration with researchers at Chalmers University in Sweden, the group has commenced research into suitable inverse techniques for microwave imaging of human tissue. Mr Scott Collis (PhD, Helium beam diagnostic) and Mr Ben Powell (MPhil, supersonic gas injector for plasma fuelling) completed their studies and submitted their theses this year.
Research on ‘BushLAN’ is driven by the goal of using a wireless system to overcome the last mile Internet connectivity problem in regional and remote areas, and was a spin-off of research into using plasma antennas for radio frequency communications. This year saw the development of several important technologies for the new (television band: VHF/UHF) BushLAN broadband system. In an excellent example of research-lead teaching, digital signal processing software for the physical layer processing and the Intermediate Frequency (IF) amplifier was developed by students in the College of Engineering and Computer Science (CECS). BushLAN is topical again this year now that the Australian Government has rekindled the regional Internet debate with a 2 billion dollar investment on regional services. It is not clear that such services could be provided within the limitations of ADSL and WiMAX, and many now consider optical fibre to the home as the only way to achieve adequate broadband data rates.
The Plasma Configurations Group is applying an innovative data mining technique to the investigation a range of Alfvén-range instabilities in the H-1 plasma. The wide range of magnetic configurations and the precise computer control of H-1 make it uniquely suitable for fundamental studies of these instabilities, the understanding of which is crucial to the success of future large experiments, such as international fusion experiment (ITER). The cross- campus collaboration with Dr M. Hegland of the Mathematical Sciences Institute has been extended internationally to include the Heliotron-J experiment in Japan, and a theoretical and computational collaboration with Dr. C. Nührenberg of the Max Planck Institute, Greifswald. In related work on plasma configurations, preliminary studies of the effect of magnetic islands on H-1 plasma have shown a possible link between island formation and the ‘Core Electron Root Confinement’ phenomenon, which improves plasma confinement.
Looking to the future, outreach and development activities included the International Summer School and Workshop on Turbulence on Coherent Structure described above, which attracted a large attendance from both novices and experts in the field. Members of the Toroidal Plasma Group played a central role in the Australian ITER forum activities to promote an Australian involvement in the international fusion experiment (ITER) project, including many outreach presentations and organisation of the highly successful international workshop ‘Towards an Australian Involvement in ITER’. Finally, continuing the restructure begun in 2005, we are pleased to welcome four new staff – Dr Frank Detering, Research Fellow (Data Mining project jointly with COSNet), Dr Hua Xia, Postdoctoral Fellow, Ms Bronwyn Stuart, Administrator and Ananda Galagali, Electronics Technician.