Summary and conclusion
Electrical
characteristic of the glow discharge were studied for H
2, N
2,
and Ar gases at different gas pressures, and discharge currents. It is found
that the (V
b) minimum breakdown voltage for Ar gas lower than that
for H
2, and N
2 gases.
The
axial floating potential distribution for the (H
2, N
2 and
Ar) gases at discharge currents was studied. The floating potential increases
rapidly near the cathode until it reaches a maximum value at the end of the cathode
fall region, (V= 190-340 volts,
X
=0.2-0.8 cm) for N
2 gas and (V= 130-230 volts, X =0.2-0.8 cm) for Ar plasma, but for H
2plasma the cathode fall extend as (V= 100-530 volts, X=0.4-1.6 cm) for H
2 plasma
The first Townsend ionization coefficient η
and the total secondary Townsend electron coefficient ω/α was determined. It
was found that the coefficient η increases by increase E/p until E/p = B after
that it decreases by increase E/p. The value of η
max is 0.0128(volt)
-1at E/p =315 (volt/torr) for N
2, and η
max for H
2is 0.0132 (volt)
-1 at E/p= 132 (volt/torr) and η
max is 0.0286(volt)
-1 at E/p =180 (volt/torr) for Ar gas, while the
coefficient ω/α decreases in narrow range by increase E/p after that it seems
to be saturated and the value of ω/α for H
2 are higher than for N
2and Ar gases.
The intensity of two emitted lines from hydrogen spectrum
(Hγ, H
β) which emits at (4341 A
0, 4861 A
0)
respectively was studied with pressures, discharge currents, discharge power,
at different position between two electrodes. The comparison between this
method and the relative continuum method take account. It found that there are
a good agreement between these method.
The intensity of two emitted lines from nitrogen spectrum
the first negative system N
2+, (as its name indicates
this system is observed in the negative column of a discharge through nitrogen
which emits strongly at 3914 A
0 (υ
`=0, υ
``=0)
and at 4278 A
0 (υ
`=0, υ
``=1) in the negative
glow, and the second positive system N
20 appears readily
in most sources notably in ordinary discharge through pure nitrogen and air,
which emits strongly at 3371 A
0 (υ
`=0, υ
``=0)
and at 3805 A
0(υ
`=0, υ
``=2) both in the
negative glow and the positive column of low pressure discharge was studied at
different pressures, different discharge currents, discharge power, and
different position between two electrodes.
The intensity of two emitted lines from argon spectrum were
studied here 4158 A
0, which emitted from neutral atom Ar
*,
and line 4348 A
0, which emitted from the first ionization Ar
+*.
The intensity of lines Hγ, H
β, N
2+,
and N
20, from the mixture of H
2, and N
2,
spectrum was studied with different pressures at different concentration of H
2in mixture, different discharge currents, discharge power, and different
position between two electrodes at constant pressure 0.25 torr.
The electron temperature of hydrogen and
mixture of hydrogen and nitrogen was determined by optical method (relative
line intensities to its continuum method). It found that, the electron
temperature of hydrogen in range (1.8- 3.5 eV) at gas pressure 0.4 torr
calculated by lines intensities of Hγ, H
β, and the electron temperature
increases with the increase in the gas pressure.
In addition, the electron temperature of mixture calculated
by the same method and it found that, it varied from (2.9-4.5 eV) and it
decreases by increasing the concentration of hydrogen in gas mixture plasma at
constant gas pressure 0.25 torr.
In addition, electron temperature of nitrogen plasma was
studied by actinometry method. A small quantity (4%) of hydrogen gas was added
to the nitrogen plasma. It is found that, the electron temperature of nitrogen
in range (4.5- 7 eV) at gas pressure 0.25 torr.
Other method take account to calculate the nitrogen
temperature, small quantity (4%) of argon gas was added to the nitrogen plasma
and the electron temperature calculated by line to line method. It is found
that, the electron temperature of nitrogen in range (3 - 3.5 eV) at gas
pressure 0.25 torr and this method has a good agreement with the temperature
calculated by line H
γ from
the above method.
موضوع: INVESTIGATIONS OF ELECTRICAL DISCHARGE FOR HYDROGEN (H2), NITROGEN (N2) AND ARGON (Ar) GASES ’’دراسة التفريغ الكهربي لغازات الهيدروجين والنيتروجين والارجون’’ 
الإثنين أغسطس 22, 2011 10:49 am