Television Image of a Large Upward Electrical Discharge Above a Thunderstorm System

Franz, R. C.; Nemzek, Robert J.; Winckler, J. R.

doi:10.1126/science.249.4964.48

Cited by 464 publications

(312 citation statements)

References 13 publications

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“…Such Trimpis associated with sprites have been called VLF sprites, a term coined by Inan et al [1995]. Here we will describe these as "cloud-ionosphere electrical discharge (CID) Trimpis" to emphasize that these are produced by ionization Rodger, 1997a, 1997b] caused by sprites which were originally attributed to cloud-ionosphere electrical discharges by their discoverers [Franz et al, 1990]. On the other hand, it has been suggested by [Inan et al, 1996a] that most early/fast events (those fitting the timing definition above) are caused by intense quasi-electrostatic fields heating ionospheric electrons.…”

Section: Introductionmentioning

confidence: 99%

Decay of whistler‐induced electron precipitation and cloud‐ionosphere electrical discharge Trimpis: Observations and analysis

Dowden¹,

Rodger²,

Brundell³

et al. 2001

Radio Science

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Abstract. There are two distinctly different causes of phase and amplitude perturbations of subionospheric VLF transmissions (termed "Trimpis"): (1) ionization enhancement in the ionospheric D region due to whistler-induced electron precipitation (WEP) and (2) modifications to the ionosphere induced directly by lightning. The latter appear to be subdivided into ionization anomalies produced by cloud-ionosphere electrical discharge (CID), or "red sprites," and heating anomalies which may not involve ionization at all. Here we consider only Trimpis (WEP and CID) produced by ionization and find that the magnitude of the Trimpi perturbation (which includes both the amplitude and phase perturbations) of both Trimpi types decays logarithmically rather than exponentially with time. While this has been previously shown for CID Trimpis, the decay of WEP Trimpis was previously thought to be exponential.

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Section: Introductionmentioning

confidence: 99%

Decay of whistler‐induced electron precipitation and cloud‐ionosphere electrical discharge Trimpis: Observations and analysis

Dowden¹,

Rodger²,

Brundell³

et al. 2001

Radio Science

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“…Since the discovery of sprites about 10 years ago [Franz et al, 1990], attention has been focused on the unusually strong (both in peak current and total charge transfer) lightning discharges known to excite these mesospheric optical emissions [Boccippio et al, 1995]. The complete nature of these strong discharges is still not known, as demonstrated by the existence of long-delayed sprites that can initiate more than 100 ms after a return stroke with no clear signature of lightning current in between Reising et al, 1999].…”

Section: Introductionmentioning

confidence: 99%

Unusually intense continuing current in lightning produces delayed mesospheric breakdown

Cummer

Füllekrug

2001

Geophysical Research Letters

103

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Abstract.Ultra low frequency magnetic field measurements made 500-2000 km from positive lightning discharges show a signature that is consistent with unusually high amplitude cloud-to-ground continuing lightning current. The magnitude of this nearly constant current moment is as large as 60 kA km and can last at half this amplitude for longer than 150 ms, thereby moving 640 C or more (assuming a 7 km vertical channel length) to the ground after the return stroke. This total charge transfer is more than an order of magnitude greater than most previously reported continuing currents in positive discharges. Three cases analyzed show this strong continuing current flows before, during, and after sprites that initiate more than 40 ms after the return stroke.Accounting for this continuing current, quantitative analysis shows that the total vertical lightning charge moment changes are large enough to produce mesospheric electrical breakdown and long-delayed sprites.

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“…Fishman et al [1994] reported that these flashes are consistent with a terrestrial origin and have hypothesized them to be related to thunderstorm activity. It is possible these flashes are related to one or more of other recently discovered upper atmospheric lightning phenomena: red sprites [Franz et al, 1990;Vaughan et al, 1992;, blue jets , or transionospheric pulse pairs [Holden et al, 1995]. Theoretical studies on the physics of high-altitude lightning have also now begun [e.g., Milikh et al, 1995].…”

Section: Introductionmentioning

confidence: 99%

Temporal and spectral characteristics of terrestrial gamma flashes

Nemiroff¹,

Bonnell²,

Norris³

1997

J. Geophys. Res.

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Abstract. We have analyzed the Burst and Transient Source Experiment (BATSE) highresolution timing data for 13 terrestrial gamma flashes (TGFs) to better characterize this newly identified phenomenon, which may be related to atmospheric lightning. We find that the minimum timescale for TGF variability is -25-250/as, with 50/as near typical. In general, TGFs are spectrally much harder than cosmic gamma ray bursts (GRBs). We additionally find that as with GRBs, individual pulses within a TGF tend to peak earlier at higher energies. This time-asymmetry rules out models such as sweeping beams. We also find that different pulses can have different spectra, with spectra typically softening as a pulse progresses. Event-averaged spectra for the TGFs were examined and found to be better fit in the 25-500 keV range by a power law than by a blackbody model. However, in general, even a power law is not a perfect fit. We find correlation between minimum TGF timescale and the power law spectral index, with rapidly varying TGFs appearing softer. From empirical comparisons of timescales and structures we speculate that if TGFs are somehow related to known high-atmospheric lightning events, then they are more probably related to red sprites than to blue jets or transionospheric pulse pairs. BackgroundTerrestrial gamma flashes (TGFs) were discovered surrendipitously by Fishman et al. [1994] In this paper we report analysis of the triggered time series of all BATSE-detected TGFs that have data in the public domain. For most of these analyses we make use of the highest temporal resolution timescale recorded by BATSE which has 2 txs time resolution. We analyzed spectra and looked for differences in the light curves of these events. In the next section we describe the data and report results, and in the last section we discuss the implications of these results on the nature of TGFs.•Now at Department of Physics, Michigan Technological University, Data and Results Energy-Dependent Light CurvesWe have analyzed all Time Tagged Event (TTE) data labelled as originating from TGFs that have entered the Compton Gamma Ray Observatory Science Support Center as public domain by July 1, 1996. BATSE TTE data are recorded in 2 txs time bins and in four energy channels, with the following approximate energy boundaries: 25-50 keV, 50-100 keV, 100-300 keV, and >300 keV. TTE data are recorded by the triggered BATSE large area detectors (LADs). Here we present TGF light curves, broken into these four energy channels, in The first detected TGF was BATSE trigger number 106. Figure la illustrates the time profiles of this TGF in the four energy channels. Inspection of these light curves immediately indicate that this TGF has at least two significant peaks. We hypothesize, in analogy to cosmic gamma ray bursts (GRBs), that this TGF is therefore composed of at least two major emission events, or "pulses." Pulses are defined as components of the time series that appear to act in a coherent way in both time and energy [Norris et al., 1986]. Pulses are hypo...

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Television Image of a Large Upward Electrical Discharge Above a Thunderstorm System

Cited by 464 publications

References 13 publications

Decay of whistler‐induced electron precipitation and cloud‐ionosphere electrical discharge Trimpis: Observations and analysis

Decay of whistler‐induced electron precipitation and cloud‐ionosphere electrical discharge Trimpis: Observations and analysis

Unusually intense continuing current in lightning produces delayed mesospheric breakdown

Temporal and spectral characteristics of terrestrial gamma flashes

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