5th INTERNATIONAL CONFERENCE ON THE FRONTIERS OF PLASMA PHYSICS AND TECHNOLOGY

18-22 April 2011, Singapore, Republic of Singapore


THE PLASMA FOCUS- NUMERICAL EXPERIMENTS LEADING TECHNOLOGY

S.H Saw1,2 and S. Lee1,2,3

1 INTI International University, Nilai, Malaysia
2 Institute for Plasma Focus Studies, Melbourne, Australia
3 Nanyang Technological University, National Institute of Education, Singapore


Abstract.  Numerical experiments on the plasma focus are now used routinely to assist design and provide reference points for diagnostics. More importantly guidance has been given regarding the implementation of technology for new generations of plasma focus devices. For example intensive series of experiments have shown that it is of no use to reduce static bank inductance L0 below certain values because of the consistent loading effects of the plasma focus dynamics on the capacitor bank. Thus whilst it was thought that the PF1000 could receive major benefits by reducing its bank inductance L0, numerical experiments have shown to the contrary that its present L0 of 30 nH is already optimum and that reducing L0 would be a very expensive fruitless exercise. This knowledge gained from numerical experiments now acts as a general valuable guideline to all high performance (ie low inductance) plasma focus devices not to unnecessarily attempt to further lower the static inductance L0. The numerical experiments also show that the deterioration of the yield scaling law (e.g. the fusion neutron yield scaling with storage energy) is inevitable again due to the consistent loading effect of the plasma focus, which becomes more and more dominant as capacitor bank impedance reduces with increasing capacitance C0 as storage energy is increased. This line of thinking has led to the suggestion of using higher voltages (as an alternative to increasing C0) and to seeding of Deuterium with noble gases in order to enhance compression through thermodynamic mechanisms and through radiation cooling effects of strong line radiation. Circuit manipulation e.g. to enhance focus pinch compression by current-stepping is also being numerically experimented upon. Ultimately however systems have to be built, guided by numerical experiments, so that the predicted technology may be proven and realized.

Paper