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 leesing@optusnet.com.au .
Machines: (right click)
List: (click on list
first, then right click to choose version)