On the dynamics of hot air plasmas related to lightning discharges: 2. Electrodynamics

Ripoll, J. F.; Zinn, J.; Colestock, P.; Jeffery, C. A.

doi:10.1002/2013jd020068

Cited by 27 publications

(33 citation statements)

References 67 publications

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“…Recently, Cooray and Rakov [] have shown that the upper limit of the peak current of first return strokes in negative lightning discharge is around 300 kA in the temperate region and 450–500 kA in the tropics. Such high currents could well lead to temperatures higher than a few hundred of thousands Kelvin according to the simulations made here and in the second part of this article [ Ripoll et al , ].…”

Section: Axisymmetric Radiative Shocks In Airmentioning

confidence: 81%

“…This could be a limitation of our model, in particular at early times when the discharge develops [cf. Ripoll et al ., ]. The chemistry detail and algorithm are discussed in .…”

Section: Gas Dynamicsmentioning

confidence: 96%

“…These motions can be seen from the nonuniform profiles of density and temperature in Figures at 1 µs around 1 cm and at 5 µs around 2 cm. The negative velocities that are then computed (not shown) have to be distinguished from the ones that could be generated by pinching effects from the magnetic field in an electrodynamics system (hydrodynamics coupled to the electrical discharge), as it will be discussed in Ripoll et al []. Such a backward motion could then be enhanced by pinching effects from the magnetic field or, on the contrary, be dominant over pinching effects, according to the values of the shock strength (i.e., energy and radius), current, and magnetic field.…”

Section: Axisymmetric Radiative Shocks In Airmentioning

confidence: 99%

“…In this paper and in its second part [ Ripoll et al ., ], we describe a series of numerical experiments that employ a comprehensive model of the lightning discharge, including radiation transport, particle diffusion, and self‐consistent electromagnetic fields and currents (only in the companion paper), intended to simulate some of the phenomena involved in a lightning discharge. We believe this is the most comprehensive numerical model for lightning devised to date.…”

Section: Introductionmentioning

confidence: 99%

“…This first paper is devoted to the radiation‐chemistry‐hydrodynamic problem involved in lightning, without solving for any electrical discharge development (including currents and E or B fields) and, instead, using the assumption of an instantaneous delivery of the initial energy into the system. In the second part of this article [ Ripoll et al ., ], a circuit model will be developed and coupled to the present gas dynamic model to attempt to capture the full electrodynamics of the lightning discharge.…”

Section: Introductionmentioning

confidence: 99%

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On the dynamics of hot air plasmas related to lightning discharges: 1. Gas dynamics

et al. 2014

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In this paper, we first study the dynamics of hot shocks in air in cylindrical geometry coupled to multiband radiation transport and detailed air chemistry. The wide energy and length scale ranges which are covered herein includes and exceeds the ones of first and subsequent return strokes happening during lightning discharges. An emphasis is put on the NO x production and the optical power emitted by strong shocks as the ones generated by Joule heating of the air from intense current flows. The production rate of NO x , which is useful for atmospheric global modeling, is found to be between 4.5 × 10 16 and 8.6 × 10 16 molecules/J for all computed cases, which is in agreement with the literature. Two different radiation transport methods are used to characterize the variability of the results according to the radiation transport method. With the exact radiation solver, we show that between 15 and 40% of the energy is lost by radiation, with a percentage between 20 and 25% for averaged lightning energies. The maximal visible peak is between 7 × 10 8 W/m and 3 × 10 7 W/m obtained for, respectively, a 19 kJ/cm and a 28 J/cm energy input. The mean radiated powers in the visible range are found between 9 × 10 6 W/m and 2 × 10 5 W/m for the energies just mentioned. We discuss the agreement of these values with previous studies.

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Section: Axisymmetric Radiative Shocks In Airmentioning

confidence: 81%

“…This could be a limitation of our model, in particular at early times when the discharge develops [cf. Ripoll et al ., ]. The chemistry detail and algorithm are discussed in .…”

Section: Gas Dynamicsmentioning

confidence: 96%

Section: Axisymmetric Radiative Shocks In Airmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the dynamics of hot air plasmas related to lightning discharges: 1. Gas dynamics

et al. 2014

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Simultaneously measured lightning return stroke channel‐base current and luminosity

Carvalho

Jordan

Uman

et al. 2014

Geophysical Research Letters

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The time delay between lightning return stroke current and the resultant luminosity was measured for 22 return strokes in eight lightning flashes triggered by the rocket-and-wire technique during the summer of 2014 in Florida. The current-to-luminosity delay measured at the channel base at the 20% amplitude level ranged from 30 to 200 ns with an average of 90 ns and at the 50% amplitude level ranged from 30 to 180 ns with an average of 94 ns. The delays are significantly shorter than that predicted by Liang et al. (2014) from theory. The current-to-luminosity delays increase with increasing current risetime, current risetime varying from 190 ns to 570 ns, but the delay appears not to depend on the peak current value.

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Optical power and energy radiated by return strokes in rocket‐triggered lightning

Quick

Krider

2017

JGR Atmospheres

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The broadband optical radiation covering the visible and near‐infrared (VNIR) spectral regions (0.4–1.0 μm) has been measured from 70 negative return strokes (RS) in rocket‐triggered lightning; 17 events were recorded in 2011, and 53 were recorded in 2012. The radiometers were calibrated, and all measurements were time‐correlated with currents measured at the channel base. The risetime and peak of an irradiance waveform are determined primarily by the RS current and by the geometrical growth and total length of channel that is in the field of view of the sensor. Following an initial peak, the irradiance decays faster than the current until there is a plateau or secondary maximum 20 to 40 μs (median of 22 μs) after the peak current, a time when the current itself is steadily decreasing. Estimates of the space‐ and time‐average optical power per unit length (ℓo) that is emitted at the source during onset of RS have been computed using the measured slopes of 70 irradiance waveforms together with an assumption that the initial speed of propagation is 1.2 × 108 m/s. The values range from 0.25 to 9.5 MW/m, with a mean and standard deviation of 2.4 ± 1.7 MW/m, and they are in good agreement with prior estimates of ℓo that were made by Quick and Krider (2013) for the subsequent return strokes in natural lightning that reilluminate a preexisting channel. The values of ℓo also agree with numerical estimates of the VNIR power per unit length that were computed by Paxton et al. (1986). Estimates of the peak optical power per unit length (ℓR) that is radiated at the source have been derived from the peaks of 53 irradiance waveforms, and the values range from 0.4 to 11 MW/m with a mean and standard deviation of 4.2 ± 2.5 MW/m. Both ℓo and ℓR are approximately proportional to the square of the peak current at the channel base. Estimates of the total optical energy per unit length, Jo, that is radiated in the VNIR have been computed by integrating the irradiance waveforms over 2 ms. The values of Jo have a mean and standard deviation of 150 ± 140 J/m, and they are proportional to the total charge that is transported to ground in that interval.

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On the dynamics of hot air plasmas related to lightning discharges: 2. Electrodynamics

Cited by 27 publications

References 67 publications

On the dynamics of hot air plasmas related to lightning discharges: 1. Gas dynamics

On the dynamics of hot air plasmas related to lightning discharges: 1. Gas dynamics

Simultaneously measured lightning return stroke channel‐base current and luminosity

Optical power and energy radiated by return strokes in rocket‐triggered lightning

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