GE 0.5 Torr and 1.8 cm Problem
The simulation was run for 46 microsecs.
Equilibrium was reached at about 25 microsecs as can be seen from the Number(t)
and Ez(t) diagnostics below.
The simulation starts off with initial Bessel function
electron and ion density profiles with axial density = 5e10/cc.
The initial number of particles was about 180 K and increased to about 320 K.
In this case, we underestimated the densities.
The following is a link to the input file:
Input File.
INPUTS
Gas is argon with the L&K cross-sectional data.
R=1.8 cm
Gas temperature = 300 K
Gas pressure = 0.5 Torr
Gas density = 1.6e16/cc (NR = 2.88e16/cm^2)
Axial current = 200 mA
XPDC1 OUTPUT
Ez = 2.6 V/cm
Electron average energy on axis = 5.2 eV
Electron density on axis = 1e11/cc
Wall potential = 16 V
The same run was done but with an overestimate rather than an
underestimate of the densities.
This simulation starts off with initial Bessel function
electron and ion density profiles with axial density = 2e11/cc.
The initial number of particles was about 700 K and decreased to about 320 K.
The following is a link to the input file:
Input File.
Equilibrium was reached at about 70 microsecs as can be seen from the Number(t)
and Ez(t) diagnostics below. So overestimating the densities is costly
since it increases the time to equilibrium and requires the use of more
particles. However, the final equilibrium was the same for both cases.
