GE FULL PROBLEM EQUILIBRIUM
John Verboncoeur's Multi-Pass Digital Filter was used to
smooth the charge density. The number of smoothing passes (nsmoothing)
was set to 400. The charge density smoothing dramatically reduced the
noise on the axis, so that we no longer saw the anomalous density
peak on axis.
The run was conducted on both processors of a Dual Pentium III 600 MHz
machine using the Parallel version of XPDC1.
The simulation was run for 35 microsecs.
Equilibrium was reached at about 25 microsecs as can be seen from the Number(t)
and Ez(t) diagnostics below. On one Dual Pentium III 600 MHz machine, this
run took about 6 days to reach equilibrium. On eight Dual Pentium
III 600 MHz machines,
the run to equilibrium would take about 3/4 of a day.
Finally, on eight Dual Pentium III
500 MHz machines the run would take (3/4)(6/5) = 0.9 of a day.
So, the GE Full Problem can now be run to equilibrium in less than a day!
The simulation starts off with initial Bessel function
electron and ion density profiles with axial density = 1e11/cc.
The initial number of particles was about 400 K.
The following is a link to the input file:
Input File.
INPUTS
Gas is argon with the original XPDC1 cross-sectional data.
R=1.8 cm
Gas temperature = 300 K
Gas pressure = 2 Torr
Gas density = 6.4e16/cc
Axial current = 200 mA
XPDC1 OUTPUT
Ez = 11.7 V/cm
Electron average energy on axis = 5.4 eV
Electron density on axis = 1.2e11/cc
Wall potential = 20 V
