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Francis G. The Glow Discharge at Low Pressure (Enc.Phys., Springer, 1956)(T)(160s).djvu |
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noticed in limited ranges of current and pressure in many gases...
Penning1, in rare gases), and also
from space potential measurements obtained by using Langmuir probes [179]
to [185]...
Lau and Reichenheim think that in hydro-
hydrogen recombination of H atoms to form H2
at the walls is necessary for the appearance
of striations [186]...
The results, referring more partic-
particularly to argon, (but similar in the other gases) may be summarised thus:
(I) Fluctuations in voltage d V, and in current, are only a few percent of the steady
value, but the light intensity varies from maximum to zero...
There are mainly
three different views about the origin of striations; they are thought to arise:
(I) At the anode or negative glow...
A negative anode fall has been observed under artificial conditions (see d);
also when the anode is placed well into the negative glow its potential is less than
plasma potential2 (Sect...
It is found that an anode
fall develops suddenly, at a critical distance D from the cathode, this point
lying towards the far (anode) end of the Faraday dark space...
In rare gases also D^>1, the length of the negative glow and it seems
unlikely that the primary electrons could penetrate so far [137], [8]...
Gun-
THERSCHULZE,BARandBETZ[200]
found both concentric rings and
spots on a plane anode surface
in a hydrogen discharge, and they explain their formation by the minimum
principle i.e...
Al—Cu—Mn—Mg) spectrographic analysis has
shown that the deposited material has exactly the same composition as the
cathode [216]...
The maximum energy transmitted from an
incident ion of energy eV, mass m, to a metal atom, mass M is
mM
at least two collisions are required to eject an atom, which has to acquire the
energy of evaporation before it can escape...
This shows a maximum at a short distance in front of the cathode,
its position depending on the velocity of ejection of the atoms (see Fig...
Preferential absorption
of certain gases often occurs and the effect is used in this way to purify small
quantities of rare gas...
The electrons accelerated
through the oxide layer lose about 20 to 50 eV energy, the amount increasing
with applied potential...
Many of these general effects, to-
together with photographs showing the
appearance of the discharge, are illus-
illustrated in recent experiments of McBee
and Dow on an unconfined glow dis-
discharge (i.e...
The current density increases
with the magnetic field, and as far as the accuracy of the
measurements allow appears to follow the law
(89.1)
where C is a constant...
When a discharge tube is placed inside a solenoid producing a longitudinal
magnetic field we must distinguish between end effects, which can be very
prominent, and the real effect of a completely uniform longitudinal field...
Cummings and Tonks tested their theory by experiments on the positive
column of a mercury arc1, at a pressure of 5 • 10~3mm...
They discuss
theoretically the radial potential
distribution and the decrease in the
gradient and electron temperature...
Later Ives 8 showed that the
effects were explicable without this postulate, and also showed that many of the experimental
results observed by Righi could be produced in suitable conditions without a magnetic field...
The dark space in front of
the anode is believed to be due to a space charge of negative ions, which controls
the current from the anode to the positive column...
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