2000-July-17: cPbL Inspec search by: Find SUBJECT RUNAWAY RELATIVISTIC TERRESTRIAL OR SUBJECT RELATIVISTIC RUNAWAY THUNDERSTORM OR SUBJECT GAMMA SPRITE OR AUTHOR LEHTINEN INAN OR SUBJECT TERRESTRIAL GAMMA LIGHTNING OR AUTHOR FISHMAN BHAT MALLOZZI 21 citations. /usr/tmp/citation.tmp.4532 @ARTICLE{InanNov99, author={Inan, U.S. and Lehtinen, N.G. and Lev-Tov, S.J. and Johnson, M.P. and Bell, T.F. and Hurley, K.}, title={ Ionization of the lower ionosphere by gamma -rays from a magnetar: detection of a low energy (3-10 keV) component }, journal={Geophysical Research Letters}, volume={26}, number={22}, year={1999}, month={Nov}, pages={3357-60}, abstract={ A gigantic periodic flare from the soft gamma repeater SGR 1900+14 produced enhanced ionization at ionospheric altitudes of 30 to 90 km, which was observed as unusually large amplitude and phase changes of very low frequency (VLF) signals propagating in the Earth-ionosphere waveguide. The VLF signals remained perturbed for À5 min and exhibited the 5.16 s periodicity of the giant flare detected on the Ulysses spacecraft (Hurley et al., 1999). Quantitative analysis indicates the presence of an intense initial low energy (3-10 keV) photon component that was not detectable by the Ulysses instrument }, keywords={ atmospheric ionisation gamma-ray effects gamma-ray sources (astronomical) ionospheric disturbances lower ionosphere ionization gamma -rays magnetars low energy component detection gigantic periodic flare soft gamma -ray repeater enhanced ionization ionospheric altitudes VLF signals low energy photon component 30 to 90 km 5.16 s 3 to 10 keV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{LehtinenNov99, author={Lehtinen, N.G. and Bell, T.F. and Inan, U.S.}, title={ Monte Carlo simulation of runaway MeV electron breakdown with application to red sprites and terrestrial gamma ray flashes }, journal={Journal of Geophysical Research}, volume={104}, number={A11}, year={1999}, month={Nov}, pages={24699-712}, abstract={ A three-dimensional Monte Carlo model of the uniform relativistic runaway electron breakdown in air in the presence of static electric and magnetic fields is used to calculate electron distribution functions, avalanche rates, and the direction and velocity of avalanche propagation. The authors also derive the conditions required for an electron with a given momentum to start an avalanche in the absence of a magnetic field. The results are compared to previously developed kinetic and analytical models and their own analytical estimates, and it is concluded that the rates used in many early models [e.g., Lehtinen et al., 1997; Taranenko and Roussel-Dupre, 1996; Yukhimuk et al., 1998; Roussel-Dupre et al., 1998] are overestimated by a factor of À10. The Monte Carlo simulation results are applied to a fluid model of runaway electron beams in the middle atmosphere accelerated by quasi-electrostatic fields following a positive lightning stroke. In particular, the authors consider the case of lightning discharges which drain positive charge from remote regions of a laterally extensive (>100 km) thundercloud, using a Cartesian two-dimensional model. The resulting optical emission intensities in red sprites associated with the runaway electrons are found to be negligible compared to the emissions from thermal electrons heated in the conventional type of breakdown. The calculated gamma ray flux is of the same order as the terrestrial gamma ray flashes observed by the Burst and Transient Source Experiment detector on the Compton Gamma Ray Observatory }, keywords={ atmospheric electricity atmospheric radiation gamma-rays lightning mesosphere mesosphere middle atmosphere electric discharge electricity electric breakdown model Monte Carlo simulation runaway MeV electron breakdown red sprite gamma ray flash gamma-ray emission lightning three-dimensional model gamma-rays relativistic runaway electron distribution function avalanche rate propagation velocity propagation direction quasi-electrostatic field optical emission }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{RodgerAug99, author={Rodger, C.J.}, title={ Red sprite, upward lightning, and VLF perturbations }, journal={Reviews of Geophysics}, volume={37}, number={3}, year={1999}, month={Aug}, pages={317-36}, abstract={ In the last decade there has been a great deal of interest in the detection and understanding of phenomena occurring above active thunderstorms. The discovery of the optical phenomena now termed "red sprites" is discussed, along with the properties that have been experimentally determined. Areas of disagreement between experimentalists are pointed out. Other optical and electromagnetic phenomena associated with red sprites are presented. These include blue jets, transionospheric pulse pairs, and gamma ray flashes. Particular attention is given to the work on perturbations on very low-frequency radio wave transmissions ("VLF sprites"), which has provided estimates of the electrical properties of sprites. Research into activity above thunderstorms will continue to lead to a greater understanding of the coupling between thunderstorms in the troposphere to the stratosphere, mesosphere, ionosphere, and beyond }, keywords={ airglow atmospheric electromagnetic wave propagation bibliographies ionosphere ionospheric disturbances ionospheric electromagnetic wave propagation lightning mesosphere reviews stratosphere thermosphere thunderstorms red sprite lightning middle atmosphere atmosphere thermosphere upper atmosphere upward lightning VLF perturbations thunderstorm optical phenomena blue jet transionospheric pulse pair ionospheric disturbance ionosphere gamma ray flash very low-frequency radio wave transmission VLF sprite radiowave propagation troposphere stratosphere mesosphere }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{Roussel-DupreMay98, author={Roussel-Dupre, R. and Symbalisty, E. and Taranenko, Y. and Yukhimuk, V.}, title={ Simulations of high-altitude discharges initiated by runaway breakdown }, journal={Journal of Atmospheric and Solar-Terrestrial Physics}, volume={60}, number={7-9}, year={1998}, month={May}, pages={917-40}, abstract={ Detailed 2D hydrodynamic and quasi-electrostatic simulations of high-altitude discharges driven by runaway air breakdown are presented for four cases, corresponding to sprites initiated by positive cloud-to-ground lightning strikes in which 200 C of charge is neutralized at an altitude of 11.5 km in 10, 7, 5 and 3 ms. We find that the computed optical emissions agree well with low-light level camera images of sprites, both in terms of the overall intensity and spatial distribution of the emissions. Our results show the presence of blue emissions extending down to 40 km (blue tendrils) and red sprite tops extending from 50 to 77 km. Simulated spectra show that N/sub 2/ 1st positive emissions dominate in the wavelength range from 550 to 850 nm, in good agreement with observations. Strong radio pulses with durations of À300 mu s and peak electric field amplitudes ranging from 20 to 75 V/m at an altitude of 80 km and an approximate distance from the discharge of 50 km were computed. The magnitude and duration of these pulses is sufficient to cause breakdown and heating of the lower ionosphere (80-95 km) and leads us to suggest that sprites may also launch the EMP responsible for the production of elves. The computed values for the gamma -ray fluxes are in agreement with observations of gamma -ray bursts of atmospheric origin and the peak secondary electron densities which we obtain are in good agreement with HF echoes at mesospheric heights and associated with lightning }, keywords={ airglow atmospheric electricity atmospheric radiation atmospheric temperature ionospheric disturbances lightning thunderstorms high-altitude discharges runaway breakdown 2D hydrodynamic simulations quasi-electrostatic simulations sprites positive cloud-to-ground lightning strikes optical emissions blue emissions N/sub 2/ 1st positive emissions radio pulses electric field heating gamma -ray fluxes secondary electron densities mesospheric heights 40 to 80 km 550 to 850 nm 11.5 km N/sub 2/ }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{BabichAug98, author={Babich, L.P. and Kutsyk, I.M. and Donskoy, E.N. and Kudryavtsev, A.Yu.}, title={ New data on space and time scales of relativistic runaway electron avalanche for thunderstorm environment: Monte Carlo calculations }, journal={Physics Letters A}, volume={245}, number={5}, year={1998}, month={Aug}, pages={460-70}, abstract={ Time and space scales of a relativistic runaway electron avalanche (RREA) t/sub i/ and l/sub i/ for a thunderstorm environment were calculated by means of a simplified MC code and a standard VNIIEF MC code ELISA, with all possible kinds of elementary interactions being taken into account. The effect of elastic scattering on RREA was analyzed. New values of t/sub i/ and l/sub i/ were used to simulate the enhancement of X-ray emission inside thunderstorm clouds due to energization and avalanche multiplication of cosmic-ray produced electrons. Results appeared to be consistent with published data obtained during flight observations inside thunderclouds }, keywords={ atmospheric electricity avalanche breakdown clouds Monte Carlo methods secondary electron emission thunderstorms electron avalanche space scales electron avalanche time scales relativistic runaway electron avalanche thunderstorm environment Monte Carlo calculations elastic electron scattering effects X-ray emission enhancement cosmic-ray produced electrons avalanche multiplication }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @CONFERENCE{Babich97, author={Babich, L.P. and Kutsyk, I.M. and Kudryavtsev, A.Y.}, title={ The effect of relativistic runaway electron avalanches on X-ray modulation inside thunderstorm }, booktitle={XXIII International Conference on Phenomena in Ionized Gases, ICPIGProceedings. Contributed Papers}, volume={}, number={}, year={1997}, month={}, pages={2-3 vol.4}, abstract={ McCarthy and Parks have reported results of flight measurements of X-rays carried out inside a space domain of a thunderstorm electric field. They have detected up to 1000 fold enhancement of X-ray flux over the background value when their plane entered a thunderstorm cloud. The measurements were arranged so as to eliminate any possible effect of electromagnetic disturbance caused by thunderstorm electromagnetic activity, on the detector used. Production of the enhanced flux terminated coincidentally with a lightning discharge. To treat the origin of this phenomenon the authors have attracted the idea that a large-scale thunderstorm electric field increased the range of high-energy electrons of the megaelectronvolt domain and thus increased the production of bremsstrahlung. These electrons are permanently generated by cosmic ray showers and by the decay of airborne radionuclides. Lightning discharges terminated the acceleration of electrons due to thundercloud voltage collapse. McCarthy and Parks have carried out calculations, results of which were 8 times lower the observed enhancement. Some additional reasons attracted by the authors to reduce the discrepancy, were not successful. In the present communication an attempt is undertaken to resolve the divergence. The calculations were based on the hypothesis of a relativistic runaway electron avalanching process in a rather weak (in comparison with the conventional laboratory self-breakdown value) thunderstorm electric field }, keywords={ cosmic ray showers discharges (electric) electric fields electron avalanches lightning thunderstorms relativistic runaway electron avalanches X-ray modulation thunderstorm X-ray flight measurements space domain thunderstorm electric field X-ray flux electromagnetic disturbance thunderstorm electromagnetic activity enhanced flux lightning discharge large-scale thunderstorm electric field high-energy electrons megaelectronvolt domain bremsstrahlung cosmic ray showers airborne radionuclides decay lightning discharges thundercloud voltage collapse relativistic runaway electron avalanching }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @CONFERENCE{Yukhimuk97, author={Yukhimuk, V. and Roussel-Dupre, R. and Symbalisty, E. and Taranenko, Y.}, title={ Optical, radio and X-ray radiation of red sprites produced by runaway air breakdown }, booktitle={XXIII International Conference on Phenomena in Ionized Gases, ICPIGProceedings. Contributed Papers}, volume={}, number={}, year={1997}, month={}, pages={52-3 vol.3}, abstract={ We use the runaway air breakdown model of upward discharges to calculate optical, radio, and X-ray radiation generated by red sprites. Red sprites are high altitude (up to 90 km) lightning discharges. Aircraft based observations (Sentman et al., 1995) show that sprites are predominantly red in color at altitudes above À55 km with faint blue tendrils, which extend downward to an altitude of 40 km; the duration of a single sprite is less than 17 ms, their maximum brightness is about 600 kR, and estimated total optical energy is about 1-5 kJ per event. The ground based observations show similar results, and provide some additional information on spatial and temporal structure of sprites (Winckler et al., 1996), and on sprite locations (Lyons et al., 1996). One difference between aircraft and ground-based observations is that blue tendrils are rarely observed from the ground. Sprites usually occur above the anvils of large mesoscale convective systems and correlate with strong positive cloud to ground discharge (Boccipicio et al., 1995). Upward discharges are the most probable source of X-ray emission observed above large thunderstorm complexes by the Compton Gamma-ray Observatory (Fishman et al., 1994). To escape the atmosphere these gamma -rays must originate above 25 km altitude. Red sprites are usually observed at altitudes higher than 50 km, and are therefore a likely source of this X-ray emission }, keywords={ atmospheric radiation brightness lightning mesosphere thermosphere optical radiation generation radiofrequency radiation generation X-ray radiation generation red sprites runaway air breakdown model upward discharges high altitude lightning discharges aircraft based observations faint blue tendrils sprite altitude sprite duration maximum brightness total optical energy ground based observations spatial structure temporal structure anvils large mesoscale convective systems strong positive cloud to ground discharge large thunderstorm complexes Compton Gamma-ray Observatory 90 km 55 km 40 km 17 ms 1 to 5 kJ }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @CONFERENCE{Symbalisty97, author={Symbalisty, E. and Roussel-Dupre, R. and Yukhimuk, V. and Taranenko, Y.}, title={ High altitude atmospheric discharges according to the runaway air breakdown mechanism }, booktitle={XXIII International Conference on Phenomena in Ionized Gases, ICPIGProceedings. Contributed Papers}, volume={}, number={}, year={1997}, month={}, pages={12-13 vol.3}, abstract={ High altitude optical transients-red sprites, blue jets, and elves-are modeled in the context of the relativistic electron runaway air breakdown mechanism. These emissions are usually with large mesoscale convective systems (hereafter MCS). In thunderstorms cloud electrification proceeds over time scale long enough to permit the conducting atmosphere above the cloud to polarize and short out the thunderstorm electric field. When a lightning strike rapidly neutralizes a cloud charge layer runaway driving fields can develop in the stratosphere and mesosphere. According to the authors' simulations of the full runaway process the variety of observed optical emissions are due to the nature of the normal lightning event in the MCS that kick starts the runaway avalanche. The authors describe some details of the model, present the results of the evolution of the primary electron population, and summarize the initial conditions necessary for different types of discharges. Two companion papers present: (a) the predicted optical, gamma ray, and radio emissions caused by these electrical discharges, and (b) the time evolution of the secondary electron population and its implications in terms of observables }, keywords={ atmospheric electricity atmospheric ionisation lightning mesosphere stratosphere mesosphere middle atmosphere lightning electric discharge high altitude atmospheric discharge runaway air breakdown mechanism optical transient red sprite red sprites blue jets blue jet elf elves relativistic electron runaway air breakdown mechanism thunderstorm cloud electrification electric field stratosphere }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @CONFERENCE{Taranenko97, author={Taranenko, Y. and Roussel-Dupre, R. and Yukhimuk, V. and Symbalisty, E.}, title={ Generation of elves by sprites and jets }, booktitle={XXIII International Conference on Phenomena in Ionized Gases, ICPIGProceedings. Contributed Papers}, volume={}, number={}, year={1997}, month={}, pages={8-9 vol.3}, abstract={ Recent years of observations of the upper atmosphere and the lower ionosphere brought a fascinating collection of new phenomena including optical, radio, and gamma-ray emissions originating in the 20 to 90 km altitude range. Up to now, the most diverse phenomenology has emerged from the optical observations which have led to the identification of red sprites, blue jets, blue starters and elves. Most of the previous studies have concentrated on relating such phenomena in the upper atmosphere to regular lightning discharges in the troposphere. For example, sprites and jets are believed to be optical manifestations of electrical discharges in the upper atmosphere caused by quasi-electrostatic fields penetrating to high altitudes during a regular lightning discharge. The sprite/jet discharge itself can be caused by the runaway air breakdown or regular air breakdown. The standard theory for optical airglow transients in the lower ionosphere above the thunderstorms also known as elves suggests that they are produced during interaction of electromagnetic pulses (EMP) from lightning with the lower ionosphere. Heating of the ambient electrons by the EMP in the D-region can result in excitation of optical emissions once the optical excitation thresholds are reached. In this paper the authors suggest that in addition to this mechanism elves can be caused by an EMP generated by sprites and jets. If sprites and jets are indeed accompanied by electrical discharges then some energy of their EMPs reaches to the ionosphere and heats ambient electrons there that in turn stimulates optical emissions similar to EMPs from regular lightning }, keywords={ airglow ionosphere lightning mesosphere stratosphere mesosphere middle atmosphere lightning stratosphere ionosphere generation formation model elves sprite jet elf red sprite blue jet blue starters electrical discharge EM pulse runaway air breakdown theory airglow electromagnetic pulse EMP D-region }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{LehtinenNov97, author={Lehtinen, N.G. and Bell, T.F. and Pasko, V.P. and Inan, U.S.}, title={ A two-dimensional model of runaway electron beams driven by quasi-electrostatic thundercloud fields }, journal={Geophysical Research Letters}, volume={24}, number={21}, year={1997}, month={Nov}, pages={2639-42}, abstract={ Intense, transient quasi-electrostatic (QE) fields, which exist above thunderclouds following a positive cloud-to-ground lightning discharge, can produce an upward travelling runaway electron (REL) beam. A new two-dimensional (2D) REL-QE model is developed, expanding the previously reported 1D model [Bell et al., 1995] and incorporating the QE [Pasko et al., 1997] and the electrostatic heating (ESH) [Pasko et al., 1997] models. The new model gives the lateral electron distribution in the beam and allows us to determine the ionospheric effects and the optical luminosities resulting from the simultaneous action of the QE fields on the ambient electrons and the runaway electrons. The model is self-consistent and includes the changes in space charge and conductivity due to the REL. Optical emissions and gamma -ray emissions [Lehtinen et al., 1996] are calculated and compared to experimental observations of sprites and terrestrial gamma -ray flashes (TGF). It is shown that the structure of the electric field and the optical emissions can be significantly affected by the REL }, keywords={ atmospheric electricity atmospheric radiation electron beams ionospheric disturbances mesosphere thunderstorms two-dimensional model runaway electron beams quasi-electrostatic thundercloud fields transient quasi-electrostatic fields thunderclouds positive cloud-to-ground lightning discharge upward travelling runaway electron beam REL-QE model electrostatic heating lateral electron distribution ionospheric effects optical luminosities space charge optical emissions gamma -ray emissions terrestrial gamma -ray flashes sprites }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @CONFERENCE{Babich97, author={Babich, L.P. and Kutsyk, I.M.}, title={ Evaluation of runaway electron avalanching }, booktitle={XXIII International Conference on Phenomena in Ionized Gases, ICPIGProceedings. Contributed Papers}, volume={}, number={}, year={1997}, month={}, pages={8-9 vol.1}, abstract={ To treat gigantic discharges directed upward from the top of thunderclouds, and possibly to explain the onset of the conventional contracted lightning, Gurevich et al. (1992) and Roussel-Dupre et al. (1994) have proposed and substantiated a hypothesis of relativistic runaway electron avalanches able to develop in a rather weak (in comparison with the conventional laboratory self-breakdown value) thunderstorm electric field. For the avalanches to develop the intensity of the electric force eE should be over the relativistic minimum of electron energy losses per unit path L/sub min/ that exists in the vicinity of electron energy epsilon approximately=1 MeV. To describe the evolution of the runaway electron avalanche and calculate a rate of a runaway electron number increase, Roussel-Dupre et al. have solved the Boltzmann kinetic equation. Results obtained infer the simplest approach assuming one-dimensional motion of electrons, is reasonable to evaluate rather accurately characteristic values of the avalanching process without solving the kinetic equation. Exactly such a model underlies the present communication, delivering results of computer simulations of the relativistic electron avalanche in air at atmospheric density }, keywords={ Boltzmann equation discharges (electric) electron avalanches lightning plasma simulation relativistic plasmas thunderstorms runaway electron avalanching gigantic discharges thunderclouds contracted lightning relativistic runaway electron avalanches thunderstorm electric field electric force intensity electron energy losses evolution Boltzmann kinetic equation one-dimensional motion electron motion kinetic equation atmospheric density air computer simulations plasma }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @CONFERENCE{Babich97, author={Babich, L.P. and Kutsyk, I.M. and Kudryavtsev, A.Yu. and Mozgovoi, A.L.}, title={ The effect of the geomagnetic field on the development of the upward atmospheric discharge }, booktitle={XXIII International Conference on Phenomena in Ionized Gases, ICPIGProceedings. Contributed Papers}, volume={}, number={}, year={1997}, month={}, pages={6-7 vol.1}, abstract={ Roussel-Dupre and Gurevich have developed a theory of gigantic atmospheric discharges directed upward from thundercloud tops into the Earth's stratosphere (1996). Formation of relativistic runaway electron avalanche initiated by cosmic-ray showers within the space domain of a thunderstorm electric field, is the heart of the theory. The theory allowed one to treat the origin of wide columns of light radiance observed repeatedly above thunderclouds. These light phenomena are known as "blue jets" emitted blue light at altitudes below 35 km, and "red sprites" emitted red light at altitudes above 60 km. Roussel-Dupre and Gurevich have pointed out that geomagnetic field affected essentially the dynamics of gas discharge processes responsible for the light emission phenomena observed, especially at high altitudes above 40 km, where electron-neutral collision frequency is reduced to become lower than local value of the electron cyclotron frequency due to lower air density. However the theory of the upward atmospheric discharges developed by now by Roussel-Dupre, Gurevich, Tunnel and Milikh, did not incorporated adequately the effect of geomagnetic field (1994). So this problem remains to be solved. Results of the first calculations carried out with the aim to evaluate the effect of the geomagnetic field on the development of the relativistic runaway electron avalanche, are delivered in the present communication }, keywords={ atmospheric electricity discharges (electric) lightning mesosphere stratosphere thunderstorms middle atmosphere mesosphere stratosphere optical emission airglow lightning red sprite magnetic field effect geomagnetic field development upward atmospheric discharge electric discharge theory gigantic atmospheric discharges thundercloud top thunderstorm relativistic runaway electron avalanche electric field blue jet dynamics gas discharge light emission }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{NemiroffMay97, author={Nemiroff, R.J. and Bonnell, J.T. and Norris, J.P.}, title={ Temporal and spectral characteristics of terrestrial gamma flashes }, journal={Journal of Geophysical Research}, volume={102}, number={A5}, year={1997}, month={May}, pages={9659-65}, abstract={ The authors have analyzed the Burst and Transient Source Experiment (BATSE) high-resolution timing data for 13 terrestrial gamma flashes (TGFs) to better characterize this newly identified phenomenon, which may be related to atmospheric lightning. They find that the minimum timescale for TGF variability is \25-250 mu s, with 50 mu s near typical. In general, TGFs are spectrally much harder than cosmic gamma ray bursts (GRBs). They 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. They 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. They 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 they 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 }, keywords={ atmospheric radiation gamma-rays lightning mesosphere stratosphere X-rays terrestrial radiation gamma ray emission spectral characteristics terrestrial gamma flash gamma ray flash atmosphere lightning red sprite TGF BATSE temporal characteristics variability time scale gamma ray spectra time-asymmetry pulse profile X-ray emission X-ray pulse model transionospheric pulse pair 25 to 500 keV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{Nemiroff96, author={Nemiroff, R.J. and Bonnell, J.T. and Norris, J.P.}, title={ Temporal and spectral characteristics of terrestrial gamma flashes }, journal={AIP Conf. Proc. (USA), AIP Conference Proceedings}, volume={}, number={}, year={1996}, month={}, pages={990-4}, abstract={ Analyzes the BATSE high time resolution data for several terrestrial gamma flashes (TGFs) to characterize this newly identified phenomenon, which may be related to atmospheric lightning. The minimum timescale for TGF variability is 40-250 mu s. In general, TGFs are spectrally much harder than cosmic gamma-ray bursts (GRBs), but as in GRBs, pulses within a TGF tend to peak earlier at higher energies and can have different spectra. Spectra for several TGFs were examined and found to be better fit in the 25-500 keV range by a power-law than a black body model. From empirical comparisons, the authors speculate that if TGFs are related to known high-atmospheric lightning events, then they are more probably related to red sprites than to blue jets or trans-ionospheric pulse pairs }, keywords={ atmospheric radiation atmospheric spectra lightning terrestrial gamma flashes temporal characteristics spectral characteristics BATSE high time resolution data newly identified phenomenon variability spectra power-law fit black body model high atmospheric lightning events red sprites blue jets transionospheric pulse pairs 25 to 500 keV }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{LehtinenSep96, author={Lehtinen, N.G. and Walt, M. and Inan, U.S. and Bell, T.F. and Pasko, V.P.}, title={ gamma -ray emission produced by a relativistic beam of runaway electrons accelerated by quasi-electrostatic thundercloud fields }, journal={Geophysical Research Letters}, volume={23}, number={19}, year={1996}, month={Sep}, pages={2645-8}, abstract={ In an experiment described by Fishman et al. [1994], high energy photons of atmospheric origin were detected by the Burst and Transient Source Experiment (BATSE) detectors, located on the Compton Gamma Ray Observatory (CGRO). In this paper the authors assess the possibility that the bursts may be bremsstrahlung produced by relativistic (>1 MeV) runaway electron beams-accelerated in an avalanche process by quasi-electrostatic thundercloud fields. They consider the height-dependent density profile of the relativistic electrons specified as a function of time in the context of a previously reported runaway model [Bell et al., 1995]. The electron beam is modeled as a vertical cylinder with radius 10 km, and numerical estimates are provided of gamma -ray fluxes which would be observed at the satellite. The predicted fluxes at the satellite altitude and at horizontal distances of up to 500 km from the source are found to be comparable to the experimental data }, keywords={ atmospheric electricity atmospheric radiation gamma-rays lightning thunderstorms atmosphere storm thunderstorm gamma ray emission gamma -ray emission relativistic electron beam runaway electrons quasi-electrostatic field electric field lightning high energy photons BATSE CGRO gamma ray burst bremsstrahlung avalanche process relativistic electrons runaway model vertical cylinder gamma -ray flux }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{InanMay96, author={Inan, U.S. and Reising, S.C. and Fishman, G.J. and Horack, J.M.}, title={ On the association of terrestrial gamma-ray bursts with lightning and implications for sprites }, journal={Geophysical Research Letters}, volume={23}, number={9}, year={1996}, month={May}, pages={1017-20}, abstract={ Measurements of ELF/VLF radio atmospherics (sterics) at Palmer Station, Antarctica, provide evidence of active thunderstorms near the inferred source regions of two different gamma-ray bursts of terrestrial origin (Fishman et al., 1994). In one case, a relatively intense steric occurring within +or-1.5 ms of the time of the gamma-ray burst provides the first indication of a direct association of this burst with a lightning discharge. This steric and many others launched by positive cloud-to-ground (CG) discharges and observed at Palmer during the periods studied exhibit slow tail' waveforms, indicative of continuing currents in the causative lightning discharges. The slow tails of these sterics are similar to those of sterics originating in positive CG discharges that are associated with sprites }, keywords={ atmospheric radiation atmospherics lightning thunderstorms terrestrial gamma-ray bursts CGRO observations sprites ELF radio atmospherics VLF radio atmospherics sterics Palmer Station Antarctica active thunderstorms source regions lightning discharge positive cloud-to-ground discharges slow tail waveforms 300 Hz to 20 kHz }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{Roussel-DupreFeb96, author={Roussel-Dupre, R. and Gurevich, A.V.}, title={ On runaway breakdown and upward propagating discharges }, journal={Journal of Geophysical Research}, volume={101}, number={A2}, year={1996}, month={Feb}, pages={2297-311}, abstract={ The origins of mysterious gamma -ray and radio flashes recently detected by satellite-based instruments passing over thunderstorms are examined in the context of upward propagating discharges initiated by runaway air breakdown. Preliminary calculations normalized by the recent optical measurements of so-called sprites indicate that the runaway mechanism may well be the source of these emissions. If this is true, then upward discharges represent the first known manifestation of a fundamental, new process in plasma physics }, keywords={ atmospheric electricity atmospheric radiation discharges (electric) lightning mesosphere plasma stratosphere thermosphere thunderstorms electric discharge mesosphere electricity middle atmosphere stratosphere thunderstorm sprite runaway breakdown upward propagating discharge gamma -ray emission mysterious gamma -ray flash radio flash runaway air breakdown calculation runaway mechanism upward discharge plasma physics thermosphere upper atmosphere gamma rays }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{TaranenkoMar96, author={Taranenko, Y. and Roussel-Dupre, R.}, title={ High altitude discharges and gamma-ray flashes: a manifestation of runaway air breakdown }, journal={Geophysical Research Letters}, volume={23}, number={5}, year={1996}, month={Mar}, pages={571-4}, abstract={ gamma -ray flashes of atmospheric origin as well as blue jets and red sprites are naturally explained by high-altitude discharges produced by runaway air breakdown. The authors present the first detailed model of the development of upward propagating discharges and compute optical and gamma -ray emissions that are in excellent agreement with observations. According to their theory, such discharges represent the first known manifestation of runaway air breakdown, a fundamental new process in plasma physics }, keywords={ airglow atmospheric electricity atmospheric radiation discharges (electric) gamma-rays mesosphere stratosphere thermosphere thunderstorms stratosphere atmospheric electricity middle atmosphere mesosphere thermosphere upper atmosphere electric discharge electric breakdown high altitude discharge gamma-ray flash runaway air breakdown gamma -ray flash blue jet red sprite model upward propagating discharge optical emission gamma -ray emission }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{McBreenDec94, author={McBreen, B. and Hurley, K.J. and Long, R. and Metcalfe, L.}, title={ Lognormal distributions in gamma-ray bursts and cosmic lightning }, journal={Monthly Notices of the Royal Astronomical Society}, volume={271}, number={3}, year={1994}, month={Dec}, pages={662-6}, abstract={ The results obtained with the Burst and Transient Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO) show that the durations of gamma-ray bursts (GRBs) are consistent with two populations. The authors report their attempts to fit lognormal distributions to various properties of GRBs. In particular, it is shown that the two populations are well fitted by lognormal distributions. Furthermore, the separations in time between the pulses of emission in long-duration, intense GRBs are also consistent with a lognormal distribution. This fingerprint of the emission process can be used to test the hypothesis of a cosmological origin for faint GRBs. The integral number versus peak flux distribution can be fitted by a truncated lognormal distribution, or by functions consisting of a single lognormal distribution with a power-law tail of slope -1.5. The lognormal properties of GRBs are similar to terrestrial lightning, and suggest that relativistic discharges between regions of charge separation may be the emission mechanism responsible for GRBs originating in the Solar System, the Galaxy or at cosmological distances }, keywords={ astrophysical radiation mechanisms gamma-ray sources (astronomical) radiation mechanism gamma ray source burster source lognormal distribution gamma ray burst cosmic lightning duration two populations emission process cosmological origin GRB peak flux distribution relativistic discharge electric discharge }, mynotes={UNREAD}, } /usr/tmp/citation.tmp.4532 @ARTICLE{FishmanMay94, author={Fishman, G.J. and Bhat, P.N. and Mallozzi, R. and Horack, J.M. and Koshut, T. and Kouveliotou, C. and Pendleton, G.N. and Meegan, C.A. and Wilson, R.B. and Paciesas, W.S. and Goodman, S.J. and Christian, H.J.}, title={ Discovery of intense gamma-ray flashes of atmospheric origin }, journal={Science}, volume={264}, number={5163}, year={1994}, month={May}, pages={1313-16}, abstract={ Detectors aboard the Compton Gamma Ray Observatory have observed an unexplained terrestrial phenomenon: brief, intense flashes of gamma rays. These flashes must originate in the atmosphere at altitudes above at least 30 kilometers in order to escape atmospheric absorption and reach the orbiting detectors. At least a dozen such events have been detected over the past 2 years. The photon spectra from the events are very hard (peaking in the high-energy portion of the spectrum) and are consistent with bremsstrahlung emission from energetic (million-electron volt) electrons. The most likely origin of these high-energy electrons, although speculative at this time, is a rare type of high-altitude electrical discharge above thunderstorm regions }, keywords={ atmospheric electricity atmospheric radiation bremsstrahlung ionosphere mesosphere thunderstorms intense gamma-ray flashes Compton Gamma Ray Observatory photon spectra bremsstrahlung emission energetic electrons high-altitude electrical discharge thunderstorm regions 30 to 80 km }, mynotes={UNREAD}, } @ARTICLE{ColgateOct69, author={Colgate, S.A. and McKee, C.}, title={ Electrostatic sound in clouds and lightning }, journal={Journal of Geophysical Research}, volume={74}, number={23}, year={1969}, month={Oct}, pages={5379-89}, abstract={ The sound pulse produced by the electrostatic stress of the cylindrical charge distribution of a lightning stepped leader has been calculated with a numerical computational program. The radial diffusion of the charge (ionic mobility) in the electrostatic field occurs simultaneously with the radial propagation of the sound pulse. The magnitude of the resulting sound pulse is approximately 300 dynes/cm/sup 2/ after propagating 5 times the original stepped leader radius. The shock and sound pulse originating from the subsequent main stroke hot air channel has been similarly calculated and duplicates previous results except for a variable gamma -law equation of state of air. The electrostatic sound pulse is roughly 1/300 of the subsequent main stroke, but, since it occurs earlier in time (10 to 100 msec), it should be detectable. The dominant frequency is roughly the same for the two sound pulses }, keywords={ atmospheric acoustics clouds electrostatics lightning terrestrial atmosphere }, mynotes={UNREAD}, }