Choose which machine you want:   Results of Numerical Experiments on Plasma Focus Machines (Scroll down to individual machines to download)


Scope:   All plasma focus machines for which we have obtained one (or more) reliable discharge current trace (analogue or digital) with indication of proper focussing action; and when bank, tube and operating parameters are available.


Procedure:   The bank, tube and operating parameters of the particular focus are input into the Lee Model code (RADPF). Initial values of axial & radial phase mass factors and current factors are also input. These (model parameters) are adjusted one by one or in combination, until the computed current trace agrees with the measured current trace in rising profile, slope & peak current, roll-over profile and current dip (position, slope and extent of dip). Very often the bank stray resistance ro is not known in which case it is initially given a trial value of 0.1(Lo/Co)0.5; and subsequently treated as another fitting parameter. This complicates the actual fitting process. Sometimes, Lo (the static inductance) as given by the researchers, is only a nominal value, and may also need to be treated as another fitting parameter. Occasionally even Co (the capacitance) especially if read off the capacitor casing, or in the case of small capacitance values of banks such as 1mF or less, may need to be adjusted. Such cases of inaccurately given Lo and Co are suspected when it is impossible to fit the traces other than to make adjustment to these values.


Results:   What you download. Results of the fitted computation are presented in 2 linked EXCEL active worksheets. The second sheet contains the measured source digital (or digitized) data and bank, tube and operational parameters. Its main feature is an active figure comparing the computed with the measured source trace, showing the best agreement achieved. The best fitted parameters are tabulated below the comparison figure. If the source data is an analogue trace it may also be displayed alongside. The first sheet contains the computed waveforms: discharge current, tube voltage, axial speed and radial speeds of current sheath, inward and reflected shocks and elongation speed during radial phase.  Plasma Temperature, thermodynamic data, and Joule, line, recombination and Bremsstrahlung yields and powers are also presented. These above listed properties of this particular plasma focus discharge are displayed in figures as well as in tabulation. Also computed and displayed are quantities such as neutron yield, pinch current, times of start of radial phase, start and end of pinch phase, etc. Each set of results is presented in active format. Hence each set of results is presented within an active universal numerical laboratory. One may change a parameter on the active sheet, say the operating voltage Vo, run the code and see the changes in the focus dynamics and properties in the first sheet as well the comparison of the newly computed current trace against the source trace. [Note: one may change all the parameters to another plasma focus, and operate that focus]


Download:    Download each Plasma Focus Machine: Place cursor against selected machine below. Right click, then left click “save target as” and select desired location e.g. ‘Desktop’. The files are 2-3 M each, if you have difficulty downloading, please e-mail    .


Machines: (right click)

PF400        PF78       Poseidon       PF1000


List: (click on list first, then right click to choose version)