Numerical Experiments Providing New Insights into Plasma Focus Fusion Devices

Abstract

Recent extensive and systematic numerical experiments have uncovered new insights into plasma focus fusion devices including the following: (1) a plasma current limitation effect, as device static inductance is reduced towards very small values; (2) scaling laws of neutron yield and soft x-ray yield as functions of storage energies and currents; (3) a global scaling law for neutron yield as a function of storage energy combining experimental and numerical data showing that scaling deterioration has probably been interpreted as neutron 'saturation'; and (4) a fundamental cause of neutron 'saturation'. The ground-breaking insights thus gained may completely change the directions of plasma focus fusion research.

Effects of Approximation and Close-Fitting Technique of Corona Model on Neon Soft X-Ray Emission in 3-kJ Plasma Focus

“…In Fig. 5, it is observed that the computed discharge current waveform agrees well with the measured current waveform, which covers all the regions of interest from axial to radial phases up to the end of the pinch phase [5], [30], [31]. The same model parameters are used for the current waveform by the Lee model for CFCM and approximated CM methods, which produce the same results, as shown in Fig.…”

“…The standard practice is to fit the computed total current waveform to an experimentally measured total current waveform using four model parameters [1], [31], i.e., the mass swept-up factor ( f m ) and the plasma current sheath factor ( f c ) for the axial phase and radial mass swept-up and current factors f mr and f cr for the radial phase [5].…”

Preliminary numerical study of Thailand Plasma Focus II (TPF-II) design

“…They obtained the results that 10 µCi activity of 18 F were produced in 3.2 kJ PF device, when operated at 10 Hz for 30 minutes. Kiai and his group 9 also showed their simulation results that 16 O( 3 He,p) 18 F and 20 Ne(d,α) 18 F reactions occurred in 150 kJ DPF device. The 1 Hz of repetition rate in 2 hours could generate 1.02 Ci and 1.79 Ci of 18 F, respectively.…”

“…The model consist of 5 phases, axial phase, radial inward shock phase, radial reflected shock phase, slow compression phase and expanded column axial phase. 16,17 A model parameter is using to fit a current waveform of a measured with the Lee model computing waveform. The fitting waveform can be separate in two parts corresponding with the phase of DPF, axial phase and radial inward phase.…”

Comparison of Measured Soft X-Ray Yield Versus Pressure for NX1 and NX2 Plasma Focus Devices Against Computed Values Using Lee Model Code

“…The inclusion of the neutron yield, Y n , using beam target mechanism [44,[54][55][56] is one the great step in the development, incorporated in the versions [54,55] of the code (later than RADPF5.13), resulting in realistic Y n scaling with I pinch [44,47,48]. The code has been used to develop scaling laws for soft X-rays [36,[57][58][59][60] and bench-mark numbers and scaling trends for ion beam flux, ion beam fluence, beam ion number, ion beam current, power flow density, and damage factor for all gases [61,62]. Application of ion beam calculations to production of short-lived radioisotopes were made by Akel et al [63].…”