The possible physical mechanism of initiation and growth of lightning

Abstract

According to insight on the liquid drop instability as for the surface electric discharge it is shown that the hitiation of lightning discharge can be related to instability of negatively charged water drops in an extemal electric field. In the total intracloud field (quasiconstant and chaotically varied in time) the large charged drops and the watered ice crystals ( R > 3 0 p ) can be unstable and start to emit highly-dispersed (r C 0.01R) heavily charged drops, unstable by the Rayleigh criterium of stability. These drops break down in a period of time of the order of tens of intrinsic oscillation periodss, emitting -100 more smaller drops. The field strength of intrinsic charges near the drop surface is sufficiently large for effective autoelectron emission (108-109V/cm). Due to the total electric field near the surface of the droplets the emitted electrons initiate electron avalanches whose characteristic linear sizes are determined by the dimensions of the space region where the coefficient of electron multiplication exceeds unity. The lifetime of one avalanche is -lO-'s. The same is the time interval between the consistent emission of two electrons by a drop. A transit of the series of consistent avalanches following the same track leads to the development of a plasma frame in the avalanche track. The overlap of the frames of adjacent avalanches in the vicinity of a group of closely located drops gives rise to formation of a plasma region (PR).The PR polarization in an intracloud quasiconstant electric field E, and its growth along E, (which is controlled by electric charges arriving into the PR from the surrounding space and originates from the charged drops instability as well as development of the ionization-avalanche processes near the PR tops) enables one to explain the phenomenon of discharge channel branching and propose a physically clear mechanism of collection of negative electric charges from separate drops carried out by lightning. A stepped leader is treated as a result of the ion-sound waves drive in the discharge channel plasma.

Study on dry band discharge of wet polluted surface with float potential metal by electro-thermal synchronous observation

“…The amplitude of pulse current is also higher than that of the test without moisture. The reason might be that the ionisation energy of moisture is lower than that of dry air [31 ].…”

Positive switching impulse discharge performance of rod‐plane short air gap under rain conditions

“…In addition to the strengthened local field, the small electron-ionisation energy of the raindrop surface (∼6.1 eV) [18], which is quite less than that of water molecule (about 12.59 eV) and oxygen molecule (about 12 eV) [19], is also of advantage to promote streamers development and reduce the U 50 under rainy condition.…”

Electrical Role for Severe Storm Tornadogenesis (and Modification)

“…Of particular note was the observation that an incremental increase of water vapor at constant temperature in the vicinity of lightning regions led to acceleration of buoyancy and ultimately greater wind updraft in the modeled cloud behavior. (Figure 3) Grigor'ev and Shiryaeva [35] have provided a modern account of lightning initiation and growth as critically-dependent on water droplets/hail/graupel in an IC atmosphere. The analysis may be compared with an earlier experimental report given by Watkins et al [36] leading to a different conclusion of relative unimportance of electrical discharges for vortex stabilization within an atmosphere of only air.…”