Application of Lee Model Curve on Fitting of Discharge Current Curve of Plasma Focus Device

A dense plasma focus is a table top machine producing a short-lived extremely popular plasma and cause fusion. Lee Model Code is a computer-based visual basic simulation package, which was successfully utilized in the plasma focus devices. The dynamics of plasma focus discharge is quite complicated, so to review and simplify the complication Lee Model couples electrical circuit with the plasma focus dynamics, radiation and therefore the thermodynamics. This enables us to simulate all of the gross focus properties. In this paper the numerical experiments are carried out to compute the current trace as a function of time for plasma focus (PF) device NX2. Results obtained by the numerical experiments are compared with the published laboratory measured data. This current fitting is completed to get the model parameters.

Optimization of neon soft X-ray yield in a low-energy dense plasma focus device

The modified version of Lee model code is used in numerical experiments for characterizing and optimizing neon soft X-ray yield ([Formula: see text]) of the United Nations University/International Center for Theoretical Physics Plasma Focus Facility (UNU/ICTP PFF) device operated at 14 kV and 30 [Formula: see text]. In our present work, the neon yield [Formula: see text] is improved with an optimized UNU/ICTP PFF device by computing the optimum combination of static inductance ([Formula: see text]), anode length ([Formula: see text]), anode radius ([Formula: see text]) and cathode radius ([Formula: see text]), keeping fixed their ratio ([Formula: see text]) at 3.368, through a lot of numerical experiments at six operating pressures ([Formula: see text]). At lower [Formula: see text] (e.g. 2.0, 2.5 and 3.3 Torr), the optimum [Formula: see text] value, together with the corresponding optimum combination of [Formula: see text], [Formula: see text] and [Formula: see text], is found to be 15 nH, whereas at higher [Formula: see text] (e.g. 4.0, 5.0 and 6.0 Torr), it is obtained as 10 nH. Though the computed maximum neon yield [Formula: see text] (57.2 J with the corresponding efficiency of 1.94%) is found at [Formula: see text], assuming an achievable range of incorporating low-inductance technology, the best optimum combination of [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] is found to be at [Formula: see text], resulting in the computed optimum neon yield [Formula: see text] of 54.60 J with a corresponding efficiency of 1.9%. This computed neon yield [Formula: see text] is about 11 times higher than the measured value [Formula: see text] at optimum [Formula: see text] of UNU/ICTP PFF. It is also observed that our computed neon yield [Formula: see text] is improved by around six times from the previously computed value, which was 9.5 J at the optimum [Formula: see text] Torr for optimum anode configuration of this machine. In addition, neon yield [Formula: see text] is obtained with our optimized combination of [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] at 11.5 kV and compared with the measured neon yield [Formula: see text] of the NX2 machine.

Modelling and Electrical Characteristics of the Thailand Plasma Focus-II (TPF-II)

The Thailand Plasma Focus II (TPF-II) is a 3.3 kJ dense plasma focus that was developed at Walailak University, Thailand. The aim of the device is to study the production of ion beams in the keV energy range and their applications for the color modification of gemstones. A high-energy ion beam is produced by heating and acceleration in the pinch phase of the plasma focus. The heating process is determined by the maximum electrical current, which can be optimized by variation of the system’s inductance. Lee model code was implemented to optimize the configuration of the electrodes. The current waveforms for the different initial conditions were used to obtain the system’s inductance, which was verified by a short circuit test. It was found that the inductance and resistance were about 153 nH and 12 mΩ, respectively.

Comparison of Plasma Dynamics in Plasma Focus Devices PF1000 and PF400

<p>In this work we have simulated two different sizes of plasma focus devices: PF400, a small sub-kJ plasma focus device in operation at the Atomic Energy Commission in Chile and PF1000, a 1 MJ device at the International Centre for Dense Magnetised Plasmas (ICDMP) in Warsaw, Poland. Our aim is to compare the plasma dynamics observed in two different sizes of the devices. We compare the experimentally obtained data with the data predicted from our numerical experiments using the Lee model code. It has been observed that the peak current of the total current waveform, pinch current calculated from total current, and neutron yield agree reasonably well with published experimental data, however, slight differences are found in other parameters.</p><p>Journal of Nepal Physical Society Vol.3(1) 2015: 55-59</p>