Atmospheric Electricity - Ultra and Extremely Low Frequency Electromagnetic Fields - page 76

Fig. 3.16 A scenario of BJ
development considered as a
positive leader-like discharge
propagating upwards at the
velocity V j (Surkov and
Hayakawa 2012 )

z , km

Streamer
zone

50

V j

40

Positive
leader

30

20

10

Earth

predominantly upward in contrast to laboratory conditions. Notice that the theory of
streamers/leaders propagating at stratospheric and mesospheric altitudes is still far
from being accurate.
It seems likely that the GJs can be associated with a large amount of negative
electric charges accumulated at the middle region of thundercloud either by chance
or as a result of another effect. One of the conceivable sets of the parameters for
existence of this situation is as follows: q i D 25, 120, 82:5 and 3 C (Krehbiel
et al. 2008 ). A model calculation of the vertical QE field is presented in Fig. 3.17
as a function of height. The numerical values of other parameters used in making
this plot are as follows: z i D 4:3, 8:0, 13:2, 15:4 km, r i D 1:1, 2:6, 1:9, 0:3 km.
As is seen from this figure, the thunderstorm electric field is close to the breakdown
threshold E s (line 1) in the area above the charge q 2 D 120 C within the altitude
range 10-12 km. This means that the GJ can be originated in this area as an upward-
propagating IC discharge which transfers a negative charge of the order of 100 C
through the region with upward/positive electric field towards the thundercloud top.
Although the field is positive in a narrow region of 13-15 km above the charge
q 3 D 82:5 C, the GJ can overcome this region to propagate out of the thundercloud
towards the ionosphere (Krehbiel et al. 2008 ;Pasko 2010 ). However, we cannot
explain in any detail why the GJs look more powerful than the BJs and why they
can extend to higher altitudes.
It appears that the most of GJs develop in the form of upward-propagating
negative leaders. In support of this conclusion it was noted that the visible