An investigation of the reconfiguration of the electric field in the stratosphere following a lightning event (original) (raw)
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Strong electric fields from positive lightning strokes in the stratosphere
Geophysical Research Letters, 2005
1] A balloon payload launched in Brazil has measured vector electric fields from lightning at least an order of magnitude larger than previously reported above 30 km in the stratosphere. During the flight hundreds of lightning events were recorded, including several positive cloud to ground lightning strokes. A two stroke flash, with small (15 kA peak current) and moderate (53 kA) positive strokes at a horizontal range of 34 km, produced field changes over 140 V/m at 34 km altitude. On-board optical lightning detection, recorded with GPS timing, coupled with ground based lightning location gives high time resolution for study of the electric field transient propagation. These measurements imply that lightning electric fields in the mesosphere over large thunderstorms may be much larger than previously measured. Citation: Holzworth, R.
Observations of lightning in the stratosphere
Journal of Geophysical Research, 1995
An examination and analysis of video images of lightning, captured by the payload bay TV cameras of the space shuttle, provided a variety of examples of lightning in the stratosphere above thunderstorms. These images were obtained on several recent shuttle flights while conducting the Mesoscale Lightning Experiment (MLE). The images of stratospheric lightning illustrate the variety of filamentary and broad vertical discharges in the stratosphere that may accompany a lightning flash. A typical event is imaged as a single or multiple filament extending 30 to 40 km above a thunderstorm that is illuminated by a series of lightning strokes. Examples are found in temperate and tropical areas, over the oceans, and over the land. 1465 ning. These include the detection of gamma-ray burst of atmospheric origin [Fishman et al., 1994], lightning-induced brightening of the airglow layer [Boeck et al., 1992], and unusual tran-ionospheric pulse pair radio signals detected by the Blackbeard experiment on the ALEXIS satellite [Holden et al.,
Atmosphere–ionosphere vertical electric coupling above thunderstorms of different intensity
Journal of Atmospheric and Solar-Terrestrial Physics, 2007
The most important features of the quasi-electrostatic fields (QSFs) and currents, generated in the region between a thunderstorm (TS) and the ionosphere between lightning discharges, are theoretically investigated. They depend on different factors having large variability, related to the TS and to the atmospheric conductivity. These features are studied in order to understand better the conditions when QSFs cause modifications of the parameters and chemical balance in the lower ionosphere over TSs due to electron heating, as well as the generation of red sprites. For this purpose, an analytical model based on Maxwell's equations under conditions of curl-free electric fields is presented. The temporal and spatial behaviour of the QSFs is studied as a function of the parameters of lightning discharges and of atmospheric conductivity. The dependence of the QSF, mainly its peak values, on the charge moment change, the discharge time, and the horizontal extent of the discharged region, on the one hand, and of the conductivity profile, on the other, is studied. It is shown that the profile of the QSF time peak changes its scale height at the altitudes where the relaxation time becomes equal to the discharge time, and where the conductivity scale height is diminished; below these altitudes the peak QSFs decrease with time much slower than above them. Also, the QSF peak increases almost linearly with the charge height and depends little on the size of the discharged region. The total Maxwell and conduction currents, which flow from the TS to the ionosphere, are also studied. The peak current is proportional to the charge moment change, and actually does not depend on the frequency of lightning discharges.
Journal of Geophysical Research, 2008
Abstract[1] Transient luminous events above thunderstorms such as sprites, halos, and elves require large electric fields in the lower ionosphere. Yet very few in situ measurements in this region have been successfully accomplished, since it is typically too low in altitude for rockets and satellites and too high for balloons. In this article, we present some rare examples of lightning-driven electric field changes obtained at 75–130 km altitude during a sounding rocket flight from Wallops Island, Virginia, in 1995. We summarize these electric field changes and present a few detailed case studies. Our measurements are compared directly to a 2D numerical model of lightning-driven electromagnetic fields in the middle and upper atmosphere. We find that the in situ electric field changes are smaller than predicted by the model, and the amplitudes of these fields are insufficient for elve production when extrapolated to a 100 kA peak current stroke. This disagreement could be due to lightning-induced ionospheric conductivity enhancement, or it might be evidence of flaws in the electromagnetic pulse mechanism for elves.
Advances in Space Research, 2005
Lightning discharges by thunderstorms cause generation of electromagnetic pulses and of quasi-electrostatic fields (QESF) in the atmosphere above, which occur in different timescales. QESF penetrate into the mesosphere and the lower ionosphere where they are big enough to generate considerable electric charge transfer there and, in some cases, to cause red sprites. These processes may have an important contribution to the global atmospheric electric circuit. Significant transient variations of the ionospheric potential above the thunderstorm take place as well. QESF depend on the atmospheric conductivity and in the ionosphere they are affected also by its anisotropy determined by geomagnetic field orientation. QESF after a lightning discharge are investigated theoretically in this work in the case of equatorial latitudes (by horizontal geomagnetic field), where thunderstorms are important contributors to the global circuit. Results for DC electric fields in the lower equatorial ionosphere above a thundercloud obtained by earlier models demonstrate some specific features of the spatial distribution of these fields, which appear due to geomagnetic field orientation. Thus, the electric fields can be shifted by tens or more kilometers to east of the cloud charge region; also their horizontal scale is much bigger than in the case of middle latitudes. Here, a presence of similar specific features of quasi-electrostatic field distributions and ionospheric potential variations caused by a lightning stroke is studied. A situation when no secondary ionization is generated is considered. A model based on the Maxwell equations for potential electric fields is proposed. Computations of QESF in the middle atmosphere and of the ionospheric potential variations are provided as dependent on conductivity and its anisotropy in D-region. The obtained results for the ionosphere show that the electric fields in the equatorial lower ionosphere are comparable to these formed in the case of middle latitudes. However, their horizontal scales are much bigger and depend on conductivity profiles. Similar features are valid also for the ionospheric potential variations and for their horizontal scales.
Radio Science, 2009
1] This paper reports the vertical electric field changes measured at 60 m and 550 m for two altitude-triggered lightning discharges and analyzes the data with two leader models. The results show that the field change waveform produced by bidirectional leader/return stroke at 60 m is asymmetrical V-shaped with the half-peak width of about 100 ms. The field waveform of the following dart leader/return stroke sequences at 60 m and 550 m also appear asymmetrical V-shaped, and the half-peak widths of the V-shaped for these two sites are 14 ms and 103 ms, respectively. The difference in the width of field waveforms can be explained by using the source charge leader model. The electric field changes of the dart leaders at 60 m and 550 m are 17.9 kV/m and 1.3 kV/m, respectively, yielding a horizontal distance dependence of d À1.18 . At very close ranges (a few tens to hundreds of meters or less), the magnitude of the dart leader field change is not different from that of the following return stroke.
Journal of Atmospheric and Solar-Terrestrial Physics, 2001
The purpose of this paper is to model numerically the ionisation created in the mesosphere above a strong horizontal (cloud-to-cloud) lightning discharge, and thus to understand better the formation of elves and related columniform (spatially structured) sprites. Such ionisation depends upon height, via the ratio of the VLF=LF wave electric ÿeld (radiated by the current in the discharge) to the atmospheric neutral density. The simulation shows local maxima on the order of 10 km apart due to the interference between direct waves radiated by the discharge current, waves re ected by the ground and waves re ected by the ionosphere. Parametric studies are carried out varying the frequency, amplitude, height, length and duration of the current. For waves ¿ 30 kHz generated by a current ¿ 50 kA, localised peaks of electron density occur from 75 to 85 km altitude, particularly for discharges longer than 15 km. From such peaks, time-varying "stalactites" on the bottom of the ionosphere, streamers could develop and propagate downwards. These could become columniform sprites in the presence of the quasi-electrostatic ÿeld due to the negative charge remaining in the thundercloud after a positive cloud-to-ground discharge.
Atmospheric electric field variations during fair weather and thunderstorms at different altitudes
Journal of Atmospheric and Solar-Terrestrial Physics, 2020
Ground-based electric field measurements during fair weather and thunderstorms are key parameters for Global Electric Circuit investigations and climate change assessment. We study the variations of near surface electric field during fair weather and thunderstorms. In this work we present daily, monthly and yearly distribution of thunderstorm activity from 2012 to 2019 at different research stations of Cosmic Ray Division (CRD) of the A. Alikhanyan National Science Laboratory (Yerevan Physics Institute) which has been done the first time for mentioned locations. The distribution of fair-weather days based on electric field variation and meteorological parameters are also discussed. According to results, thunderstorm activity is very high from May to June and the most active part during the day is from 15:00 to 20:00 LT at three different altitudes.
2016
We present simultaneous current and wideband electric field waveforms at 380 km associated with upward flashes initiated from the Säntis Tower. To the best of the authors' knowledge, the presented dataset in this study includes the first simultaneous records of lightning currents and associated fields featuring ionospheric reflections, and the longest distance at which lightning fields have been measured simultaneously with the current. Electric field data are used to evaluate ionospheric reflection characteristics during day and night times using the socalled zero-zero and peak-peak methods. During daytime, the estimates for the ionospheric reflection height is about 80 km, corresponding to the D layer. The estimated height at night time is about 90 km, corresponding to the E layer. Finally, we present a full-wave, finite-difference time-domain (FDTD) analysis of the field propagation including the effect of the ionospheric reflection and compare the results with experimental data.
Journal of Atmospheric and Solar-Terrestrial Physics, 2017
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