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
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 ).
Search WWH ::

Custom Search