Geoscience Reference
In-Depth Information
A capacity-coupled high-frequency discharge is ignited and burned near a contact
gas-mixing surface in the co-flow (near a high gas density gradient region) as a
rule automatically. Modulated CHFD disturbs this contact surface and generates
intensive acoustic waves and the gas turbulence. So, capacity-coupled high-
frequency discharge can intensify a co-flow mixing of two jets.
Fast transportation of the marked ions of a testing gas, injected in high-frequency
filament, is found. The typical velocity of this marker ion transportation inside
the high-frequency filaments is about
V
fl
10
3
m/s, or higher.
The high-frequency filament in the high-speed gas flow (at the flow Mach number
M
D
1.2-2 and pressure
P
st
< 10
5
Pa) has extremely high plasma parameters. Ac-
cording to our measurements, the electron concentrations
N
e
are
N
e
10
15
cm
3
inside the streamer and
N
e
10
12
to 10
13
cm
3
between the streamers. Specific
energy storage
Q
inside the streamer is
Q
1-10 J/cm
3
.
Rotation temperature (
T
R
) of the excited nitrogen molecules in this filamentary
discharge in the high-speed airflow is about
T
R
D
1,200 K.
Vibration temperature (
T
V
) of the excited nitrogen molecules in this filamentary
discharge in the high-speed airflow is about 4,000 K.
The
T
R
and
T
V
values depend considerably on high-frequency discharge
parameters and airflow parameters. Thus, a high-frequency plasma filament is a
nonequilibrium high-energetic plasma formation in the high-speed airflow.
6.3
Stable Longitudinal High-Frequency Discharge Plasmoid
in Swirl Airflow
The longitudinal vortex plasmoid created by the capacity-coupled high-frequency
discharge in swirl flow has additional important physical properties closely resem-
bling those of natural BL.
The experimental setup SWT-1 used in our experiments was described in detail
(Kilmov et al.
2011
; Klimov and Moralev
2008
). This setup SWT-1 was designed
and manufactured to study a longitudinal vortex plasmoid created by a capacity-
coupled high-frequency discharge in a tube in swirl airflow at high pressure
P
st
10
5
Pa and the maximal tangential velocity
V
t
40 m/s (Fig.
6.1
). The setup
consists of a swirl generator, a quartz tube (testing chamber), a high-frequency
generator with a high-voltage Tesla transformer, high-frequency electrodes, and
diagnostic instrumentation. The swirl generator was connected with a compressor.
This modified setup, SWT-1M, was manufactured to study a longitudinal vortex
plasmoid created by a longitudinal vortex in high-speed swirl flow at low static pres-
sure,
P
st
D
5
10
3
to 5
10
4
Pa, and the maximal tangential velocity
V
t
140 m/s.
This setup was equipped with a vacuum chamber with a vacuum pump.
