Convective Cooling of Lightning Channels

Picone, J. M.; Boris, J. P.; Greig, J. R.; Raleigh, M.; Fernsler, R. F.

doi:10.1175/1520-0469(1981)038<2056:ccolc>2.0.co;2

Cited by 61 publications

(35 citation statements)

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“…Increasing the temperature to 3000 K increases the production rate of NO such that the total number of available nitrogen atoms is converted to NO in 2.60 × 10 −6 s. At 4000 K, NO production rates are the greatest (Table 2 and Fig. 3), in agreement with Picone et al (1981). It should again be noted that total conversion of nitrogen atoms does not imply total conversion of all nitrogen to NO; the quantity of NO produced is limited by the dissociation of nitrogen molecules.…”

Section: Resultssupporting

confidence: 53%

“…Air within the hot core mixes with surrounding air (Picone et al, 1981), providing a supply of reactants in the near vicinity. Ice crystals in the surrounding corona sheath would survive, and are still in sufficient proximity to the lightning channel to participate in catalytic reactions.…”

Section: Stability Of Ice Crystals At High Temperaturesmentioning

confidence: 99%

“…Rakov and Uman (2003) estimate the lightning channel to be 1 to 2 cm in radius. The problem is nonlinear as the channel expands until the core temperature has reached 3000 K (Picone et al, 1981). The process is further complicated by the potential for dart leaders to form in the lightning channel between 2000 and 4000 K (Uman, 1984).…”

Section: Introductionmentioning

confidence: 99%

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Possible catalytic effects of ice particles on the production of NO<sub>x</sub> by lightning discharges

Peterson

Beasley

2011

Atmos. Chem. Phys.

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Abstract.It is well known that lightning produces NO x as a result of the high temperatures in discharge channels. Since most viable proposed electrification mechanisms involve ice crystals, it is reasonable to assume that lightning discharge channels frequently pass through fields of ice particles of various kinds. We address the question of whether ice crystals may serve as catalysts for the production of NO x by lightning discharges. If so, and if the effect is large, it would need to be taken into account in estimates of global NO x production by lightning. In this theoretical study, we make a series of plausible assumptions about the temperature and concentration of reactant species in the environment of discharges and we postulate a mechanism by which ice crystals are able to adsorb nitrogen atoms. We then compare production rates between uncatalyzed and catalyzed reactions at 2000 K, 3000 K, and 4000 K, which are reasonable temperatures in lightning channels as they cool down. Ice crystal catalysis is expected to produce 2.7 times more NO than if ice crystals were not present. Catalyzed NO production rates are greater at 2000 K, whereas uncatalyzed production rates are greater at 4000 K. Thus, temperatures that favor rapid NO production without ice crystals adsorbing nitrogen atoms are unfavorable for NO production in the presence of ice crystals, and vice versa. The density of atmospheric ice crystals is much larger at 10 km where intracloud (IC) flashes peak than at 5 km where cloud to ground (CG) flashes peak, thus catalytic processes are expected to be more important for IC flashes than CG flashes, perhaps explaining a portion of the discrepancy in IC and CG production rates.

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Section: Resultssupporting

confidence: 53%

Section: Stability Of Ice Crystals At High Temperaturesmentioning

confidence: 99%

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Possible catalytic effects of ice particles on the production of NO<sub>x</sub> by lightning discharges

Peterson

Beasley

2011

Atmos. Chem. Phys.

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“…The experimental data do not support this possibility, however. 5 Another possibility is the rapid movemeit of the discharge current axis which could result from magnetic forces present when the current is nonnegligible. This could, in turn, displace the surrounding air sufficiently to produce some long-term mixing motion.…”

Section: [I Mechanisms For Convective Coolingmentioning

confidence: 89%

Vorticity generation by asymmetric energy deposition in a gaseous medium

Picone

1983

The Physics of Fluids

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We develop a detailed theory of vorticity generation by asymmetries which are present when a cylindrical pulse of energy is deposited in a gaseous medium. Three classes of asymmetry which may occur separately or in combination, depending on the experiment being analyzed, are identified. A convenient representation of the flow field in terms of one or more vortex filament pairs having identical strengths is also introduced. The equations which give the vortex filament strength for the various asymmetry classes differ only in the value of a form factor, which contains information regarding geometric effects and hydrodynamic interactions. The form factor, however, depends only weakly on the profile of the density distribution of the medium prior to energy deposition. Finally the analytic results are verified and calibrated by providing data from accurate two-dimensional simulations of several cases. The analytic and numerical calculations agree closely for all examples considered.

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“…(As a result the channel's cooling and expansion rates speed up significantly) This kind of a cooling regime may be realized, for instance, after the interruption of powerful spark discharges [34][35][36][37], pulse arcs and laser sparks [37,38]. It is possible (It may be supposed) that the dynamics of the channel decay of natural lightning as well as that in a long artificial spark, which models it, is also defined by the formation of a turbulent flow in the after-discharge channel [39]. The dependence of the gas cooling process characteristics on a relatively small residual current in the channel has been demonstrated for the first time in (paper) reference [40].…”

Section: Eoard-jiht Ras-istc May 2013mentioning

confidence: 99%

Study of Mechanisms of Filamentary Pulse Electric Discharge Interaction with Gaseous Flow of Nonuniform Composition

Leonov¹

2013

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Convective Cooling of Lightning Channels

Cited by 61 publications

References 0 publications

Possible catalytic effects of ice particles on the production of NO<sub>x</sub> by lightning discharges

Possible catalytic effects of ice particles on the production of NO<sub>x</sub> by lightning discharges

Vorticity generation by asymmetric energy deposition in a gaseous medium

Study of Mechanisms of Filamentary Pulse Electric Discharge Interaction with Gaseous Flow of Nonuniform Composition

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Convective Cooling of Lightning Channels

Cited by 61 publications

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Possible catalytic effects of ice particles on the production of NO&lt;sub&gt;x&lt;/sub&gt; by lightning discharges

Possible catalytic effects of ice particles on the production of NO&lt;sub&gt;x&lt;/sub&gt; by lightning discharges

Vorticity generation by asymmetric energy deposition in a gaseous medium

Study of Mechanisms of Filamentary Pulse Electric Discharge Interaction with Gaseous Flow of Nonuniform Composition

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Possible catalytic effects of ice particles on the production of NO<sub>x</sub> by lightning discharges

Possible catalytic effects of ice particles on the production of NO<sub>x</sub> by lightning discharges