REPUBLIC OF SINGAPORE - NANYANG

NANYANG TECHNOLOGICAL UNIVERSITY
NATIONAL INSTITUTE OF EDUCATION
NATURAL SCIENCES

1 Nanyang Walk, Singapore 637616

Telephone: +65 460 5300
Telefax: +65 469 8952
E-mail: svsprin@nie.edu.sg
URL:   http://www.nie.ac.sg:8000/~wwwphys/index.htm

Plasma Focus Group

Lee, Paul (Leader)
Cecilia, Selvam
Feng, Xianping (soft x-ray spectroscopy)
Gribkov, Vladimir***
Koudryachov, Vladimir

Lee, Sing
Liu, Mahe
Pasquale, Petrella**
Springham, Stuart Victor (Ion beams)
Wong, Terence* (SXR lithography)

Research activities:
Speed enhanced neutron scaling: work with stepped anode having a second section with enhanced current per unit radius shows evidence of extension of neutron yield scaling to above I⁴. This work is carried out in the UNU/ICTP PFF device (United Nations University/International Centre for Theoretical Physics Plasma Focus Facility) supported by neutron yield counters, neutron TOF spectroscopy, laser shadowgraphy and soft x-ray spectroscopy (S. Lee, A. Serban: Speed enhanced neutron yield in Plasma Focus. International Conf. on Plasma Physics, Foz do Iguassu, Brasil, Oct 1994. Vol 1, 181-184; also IEEE Trans Plasma Sc. 24, 1996, 1101-1105).

Radiative Plasma Focus: study incorporating thermodynamical quantities during the radiative phase especially in neon in order to model soft x-ray emission; comparison of modelling with experiments is being carried out both in the UNU/ICTP PFF device and repetitive devices, the Nanyang Technological University/National Institute of Education Soft X-ray Source (NNSX1 & NNSX2). Motivation is the development of repetitive high power radiation sources. We have achieved SXR powers of 300W (wavelength range of 0.8-1.4 nm), averaged over the duration of one minute at 10 pps (S. Lee, P. Lee, G.X. Zhang, V.A. Gribkov, X. Feng, M.H. Liu, A. Serban: High Repetition, High Performance Plasma Focus as a Radiation source. International Symp. on Plasma Research and Applications. Opole Jarnoltowek, Poland, 10-12 June 1997).

Development of didactic package based on a small plasma focus (UNU/ICTP PFF) for international training programmes aimed at initiating/strengthening experimental plasma research; collaborative work in conjunction with the International Centre for Theoretical Physics, the Asian African Association for Plasma Training and the proposed International Centre for Dense Magnetised Plasmas. (S. Lee et al: American J. Physics 56, 1988, 62-68; S. Lee: Chinese Physics Letters 10, 1993, 33-41; also J. Moscow Physical Soc. (Series B) ``Physics in Higher Education'' 1, 1995, 99-126; also Pulsed Plasmas for Technology, Training and Cooperation. International Symp. for Cooperation in Plasma Science and Technology, UNU, Tokyo, Japan, Sep. 16-19 1996).

Charged Particle Studies: work employing Solid-State Nuclear Track Detectors (SSNTDs) in combination with a computer controlled automated detector scanning system based on an optical microscope with motorized stage and focus adjust. In recent work we have used SSNTDs and a camera obscura to form an axial image of the fusion proton production region within the plasma focus. These studies provide strong evidence that the beam-target mechanism is responsible for some 90 to 96% of the fusion within our small (3kJ) plasma focus device. However, there is also clear evidence that 4 to 10% of the fusion occurs within the pinch region, but it is not determined if this fusion contribution is thermo-nuclear in nature, or some other mechanism is responsible. (S.V. Springham et al: 14th IAEA Technical Committee Meeting on Research Using Small Fusion Devices, Sao Paulo, Brazil, 25-27 June 2001).

* EEE, NTU; ** MPE, NTU; *** Lebedev Physical Institute, Moscow