The changes on physical characteristics of lightning discharge plasma during individual return stroke process

He, X. T.; Pan, Yuan; Cen, Jianyong; Zhang, Guangshu

doi:10.1063/1.4869460

Cited by 9 publications

(3 citation statements)

References 24 publications

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“…Emissions in the near infrared (NIR) are mostly dominated by neutral nitrogen and oxygen and H α emissions, with also a few emission lines from ionized nitrogen. More recently, Xu et al [] study the correlation between the spectral information, the electron density, the channel temperature, and the gas pressure. They concluded that the total intensity of spectra is positively correlated to the intensity of spectral line and they both rapidly decrease with time.…”

Section: Introductionmentioning

confidence: 99%

Temporal and radiometric statistics on lightning flashes observed from space with the ISUAL spectrophotometer

et al. 2015

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The Imager of Sprites and Upper Atmospheric Lightning (ISUAL) on the FORMOSAT-2 satellite was launched in 2004 and records transient luminous events (TLEs). ISUAL is an instrument composed of an imager and a multichannel spectrophotometer which is able to measure the brightness from far ultraviolet to near infrared for TLEs and lightning flashes. Several types of TLEs have been identified, classified, and documented between 2004 and 2014. However, no statistical analyses on lightning have already been realized. In this paper, we focus on lightning flashes which did not induce TLEs. Statistics about brightness or temporal dynamic are presented from fitted waveforms from far ultraviolet to near infrared, after having corrected for atmospheric effects for each spectrophotometer channels. We demonstrate that the lightning/satellite distance and the altitude of the lightning need to be taken into account. The lightning waveforms from each spectrophotometer channel could be modeled as an exponential pulsed function which the shape could be explained by the photon propagation in the cloud. The median values at 777.4 nm are 1.63 × 10 À6 W m À2 for the maximum brightness, 5.85 × 10 4 J for the total energy at the source, 414 μs for the full width half maximum, 620 μs for the full width at quarter of maximum, and 170 μs for the risetime. Results are compared with previous experiments performed from visible to near-infrared domains. The median temporal variables for near-infrared waveforms are shorter than the values of the UV waveforms.

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Section: Introductionmentioning

confidence: 99%

Temporal and radiometric statistics on lightning flashes observed from space with the ISUAL spectrophotometer

et al. 2015

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“…1, 7 The lightning channel, heated by strong discharge current, can reach a peak temperature of about 30 000 K, thus forms a plasma channel. 8,9 Analysis on lightning spectrum is an effective way to learn the physical parameters of the plasma channel, which is mainly studied in the 1960s and early 1970s. 10 Most works focused on the investigation of the channel temperature.…”

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confidence: 99%

Resistance and internal electric field in cloud-to-ground lightning channel

Cen

Pan

Xue

et al. 2015

Applied Physics Letters

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Cloud-to-ground lightning with six return strokes has been recorded by slitless spectrograph and the system of fast antenna and slow antenna. The physical parameters of the discharge channel have been obtained based on the combination of spectra and synchronous radiated electric field. The resistance and internal electric field of the channel are studied as the focus in this paper. The results show that the resistances per unit length of the lightning channel are in the order of 10 À2 -10 À1 X/m and the internal electric field strengths are in the order of 10 3 V/m. V C 2015 AIP Publishing LLC.[http://dx.doi.org/10.1063/1.4907287] Cloud-to-ground (CG) lightning is a large scale electric discharge with strong current flowing through the channel and intense electromagnetic radiation. The study on electrical characteristics of CG lightning has always been an important research subject in the field of lightning protection. 1-6 The CG lightning discharge usually starts in the cloud and brings lots of charges to the ground. It is made up of various discharge processes, among which are typically several highcurrent pulses called return strokes. The time interval between two adjacent return strokes is typically several tens of milliseconds. Sometimes a relatively low level continuing current may immediately follow the return stroke. 1,7 The lightning channel, heated by strong discharge current, can reach a peak temperature of about 30 000 K, thus forms a plasma channel. 8,9 Analysis on lightning spectrum is an effective way to learn the physical parameters of the plasma channel, which is mainly studied in the 1960s and early 1970s. 10 Most works focused on the investigation of the channel temperature. [11][12][13] Owing to the low luminous sensitivity of equipment, it is very difficult to obtain the high resolved spectrum. In the subsequent 40 years, there is almost no progress on the physical characteristics of discharge channel by using lightning spectrum. Instead, recording the radiated electric field has become the main method to study the lightning, which is still in use up to now. 14-16 With the arrival of high-speed and high-sensitivity imaging equipment, combination of time-resolved spectrum and radiated electric field will provide more detailed information for the physical characteristics in lightning processes. 3,10 Resistance and internal electric field in lightning channel are two important parameters that directly represent the electrical characteristics of lightning. Many electromagnetic models of lightning channel inferred that the resistances were in the range from 0.07 to 1 X/m and the internal electric field was in the order from 10 3 to 10 4 V/m. 17-20 But, these results are theoretically, there are no experimental results on these two parameters.In this letter, according to lightning spectra captured by slitless spectrograph, the temperature, electron density, electrical conductivity, and resistance of lightning plasma channel are obtained. Based on the synchronous radiated electric field recorded by ...

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“…In other words, the temperature of the return stroke channel is still >20000 K after the current drop to half‐peak values. Because of the continuous action of the current, the attenuation of the temperature is slower than that of the current (Xu et al, ). The return stroke channel can maintain a high temperature for a comparatively longer time.…”

Section: Experiments and Analysismentioning

confidence: 99%

Using Saha‐Boltzmann Plot to Diagnose Lightning Return Stroke Channel Temperature

Liu

Pan

et al. 2019

JGR Atmospheres

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Based on the high time‐resolved spectra of a cloud‐to‐ground lightning flash with seven return strokes captured by a high‐speed slitless spectrograph, this work was the first to use the Saha‐Boltzmann plot method for the determination of the lightning return stroke channel temperature. The channel temperatures of the seven return strokes ranged from 21370 to 26500 K. Compared with the traditional Boltzmann plot method, the Saha‐Boltzmann plot method can provide more reliable temperature estimation for lightning channel. Analysis of several strong return strokes along the channel showed that the temperature changed little and there was no obvious tendency with increasing height. In addition, it was found that the channel temperature in the late stage of a return stroke was only about 3000–4000 K lower than in the initial stage. This means the channel remains >20000 K during nearly the entire period of the return stroke. This sustained high temperature could be the main cause of lightning‐related disasters.

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The changes on physical characteristics of lightning discharge plasma during individual return stroke process

Cited by 9 publications

References 24 publications

Temporal and radiometric statistics on lightning flashes observed from space with the ISUAL spectrophotometer

Temporal and radiometric statistics on lightning flashes observed from space with the ISUAL spectrophotometer

Resistance and internal electric field in cloud-to-ground lightning channel

Using Saha‐Boltzmann Plot to Diagnose Lightning Return Stroke Channel Temperature

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