Geoscience Reference
In-Depth Information
Fig. 6.2
Longitudinal vortex plasmoid created by a single high-frequency (
HF
) electrode in free
space between two separated quartz tubes.
1
and
3
quartz tubes,
2
the “hot” high-frequency
electrode
The typical relative ratio
K
D
E
crit
/
E
HF
in this vortex plasmoid has been measured
as about
K
D
10-100, where
E
crit
is the electric breakdown field, and
E
D
U
/
L
(
U
is output high-frequency potential,
E
is the mean electric field intensity, and
L
the
typical plasmoid length).
It is proven that the value
K
D
100 is too small to create the self-sustained
capacity-coupled high-frequency discharge at atmosphere pressure (
L
100 cm,
U
40 kV). Actually, the relative electric field is about
E
/
N
3-6
T
d
,andthe
average gas temperature inside a longitudinal vortex plasmoid is about
T
g
D
600-
1,200 K (see following). This value of
E
/
N
is very small in comparison with the
air breakdown field (the typical value of which, in air at atmospheric pressure, is
30 kV/cm), and it cannot realize an electric air breakdown and create a pulsed
repetitive discharge. Thus, the physical mechanism of the creation of this subcritical
vortex plasmoid in swirl airflow is not clear at present.
It was shown that this capacity-coupled high-frequency discharge propagates
toward the oncoming airflow. This result can be connected with a reverse flow
creation in swirl flow at a definite vorticity parameter value (Klimov
2009
). Note
that this type of high-frequency plasmoid is similar to BL and bead lightning going
out of an electrical socket during thunderstorms (Grigorjev
2006
; Bychkov and
Bychkov
2006
).
Different types of longitudinal plasmoids were created by capacity-coupled
high-frequency discharge in swirl airflow at various mass flow rates in the range
2 <
Q
< 10 G/s (or different flow velocities), and the various high-frequency power
has values in the range 0.1<
P
HF
< 1kW(Fig.
6.3
). Co-flow plasmoids (frames 1,
2), counterflow plasmoids (frames 5-7), and combined forms (frames 3, 4) were
created in the gas swirl flow (Fig.
6.3
). The type of these longitudinal plasmoids is
determined by the value
Q
(or of the tangential velocity) and of the value of the
high-frequency power input in
P
HF
. Therefore, these vortex plasmoids can move
against a wind, as can do some observed BL (Grigorjev
2006
).
