Specifying input parameters
Plasma-producing gas
If you
wish to work with a pure monoatomic plasma-producing gas, just enter in
this field the chemical symbol, e.g., He.
The
first character must be non-blanc. Observe the difference between
upper and lower-case letters. This version of our database includes, but
is not limited to, He, Ne, Na, Ar, Cu, Kr, Xe, Cs, and Hg; if the gas
you wish to work with is not in the database, the code will issue an
error message and terminate.
This
version of the database allows also working with the following mixtures:
air (entry:
ai),
mixture Na-Hg (entry: NH),
mixture Cs-Hg (entry: CH),
plasmas of mercury with addition of metal halides (entry:
MH;
the percentage of additives is assumed to be small), plasmas of xenon
with addition of metal halides (entry:
XH;
the percentage of additives is assumed to be small).
Plasma pressure
Enter
pressure of the plasma (in bars).
Cathode material
Enter in
this field the chemical symbol of metal which the cathode is made of,
e.g.,
W.
The first character must be non-blanc; for example,
‘W ’
is
permitted while ‘ W’
will cause
an error message and the code will terminate. Observe the
difference between upper and lower-case letters. This version of our
database includes, but is not limited to, W, Mo, Fe, Nb, and Zr; if the
metal you wish to work with is not in the database, the code will issue
an error message and terminate.
Cathode radius
Enter radius of the cathode (in m).
Cathode height
Enter height of the cathode (in m).
Temperature of the base
Enter
temperature of the base of the cathode (in K).
Radiation
Enter
.t.
if you wish to take into account the cooling of the front and lateral
surface of the cathode by radiation and
.f. if you wish to
neglect the radiation cooling.
Insulated lateral surface
Normally,
this parameter is set equal to
.f..
If you set this parameter equal to .t.,
then densities of the electric current and the energy flux from the
plasma to the lateral surface of the cathode are set equal to zero. In
other words, .t.
corresponds to the case where the lateral surface of the cathode is
electrically and thermally insulated. (This case is of theoretical
interest because the diffuse-mode solution in this case is
one-dimensional.)
Variability of the work function
Enter .t.
if you wish to take into account the variation of the work function of
tungsten covered with sodium (plasma-producing
gas =
NH) or
cesium (plasma-producing gas = CH)
atoms. If this field reads .f.,
the value of work function for uncovered metal will be assumed.
Attention: if this field reads .t.,
then cathode should be W
and gas either NH
or CH, otherwise the code will issue an error message and terminate. Note
that calculations with account of variation of the work function require
special care, especially in the case of
CH plasma.
Content of sodium
If your plasma-producing gas
is NH,
or MH,
or XH,
enter in this field the mole fraction of the element of sodium in the
mixture. This field has no effect if your plasma-producing gas
is
neither NH nor MH
nor XH.
Content of thallium
If your plasma-producing gas
is MH
or XH, enter in this field the mole fraction of the element of thallium in
the mixture. This field has no effect if your plasma-producing gas
is neither MH
nor XH.
Content of dysprosium
If your plasma-producing gas
is MH
or XH, enter in this field the mole fraction of the element of dysprosium in the
mixture. This field has no effect if your plasma-producing gas
is neither MH
nor XH.
Content of scandium
If your
plasma-producing gas
is
MH
or XH,
enter in this field the mole fraction of the element of scandium in the
mixture. This field has no effect if your
plasma-producing gas
is neither
MH
nor XH.
Content of cesium
If your
plasma-producing gas is CH, or MH, or XH, enter in this field the mole fraction of the element of cesium in the
mixture. This field has no effect if your
plasma-producing gas is
neither CH
nor MH
nor
XH. Content
of zinc
If your
plasma-producing gas
is XH, enter in this field the mole fraction of the element of zinc in the
mixture. This field has no effect if your
plasma-producing gas is
not XH.
Content of indium
If your
plasma-producing gas is XH, enter in this field the mole fraction of the element of indium in the
mixture. This field has no effect if your
plasma-producing gas is
not XH.
Content of thorium
If your
plasma-producing gas is XH, enter in this field the mole fraction of the element of thorium in the
mixture. This field has no effect if your
plasma-producing gas is
not XH.
Content of iodine
If your
plasma-producing gas is XH, enter in this field the mole fraction of the element of iodine in the
mixture. This field has no effect if your
plasma-producing gas is
not XH.
In the
case of metal halide plasmas (MH)
the code evaluates mole fraction of the element of iodine assuming that
the metal halides are added to mercury in the form of molecules NaI,
TlI, DyI3, ScI3, CsI. In other words, mole
fraction of the element iodine is evaluated in terms of mole fractions
of the elements Na, Tl, Dy, Sc, and Cs as ZI = ZNa+ZTl+3(ZDy+ZSc)+ZCs. It
is assumed that the only element of metal halide plasmas besides Na, Tl,
Dy, Sc, Cs, and I is Hg, i.e., the code assumes
ZHg = 1-(ZNa+ZTl+ZDy+ZSc+ZCs+ZI).
In the case of plasmas of
xenon with addition of metal halides (XH),
it is assumed that the only element of the plasmas besides Na, Tl, Dy, Sc, Cs, Zn, In, ZTh, and I is Xe, i.e., the code assumes
ZXe = 1-(ZNa+ZTl+ZDy+ZSc+ZCs+ZZn+ZIn+ZTh+ZI).
Example
This
tutorial refers to the following example, unless other conditions are
specified. Suppose that you wish to simulate interaction of an
atmospheric-pressure argon plasma with a tungsten cathode of the radius
of 1 mm and of the height of 10 mm, with the temperature of 200C
at the externally cooled base of the cathode, without insulation on the
lateral surface of the cathode, taking into account cooling of the
cathode by radiation. In this case, you should specify:
Ar ! plasma-producing gas
1 ! plasma pressure in bars
W ! cathode material
0.001 ! cathode radius in m
0.010 ! cathode height in m
293 ! temperature of the cathode
base in K
.f. ! insulated lateral surface
.t. ! radiation
.f. ! variability of the work
function
Contents of the fields
Content of sodium, Content of thallium, Content
of dysprosium, Content of scandium, Content of cesium, Content of zinc,
Content of indium, Content of thorium, Content of iodine
are irrelevant.
When all relevant input
parameters have been specified, press the
Submit button to transfer
the information to the server.