An optical flash on Venus detected by the AKATSUKI spacecraft

Abstract Detection of lightning discharges on Venus has been attempted using both radio waves and optical methods for over 40 years. For optical observations, claims of lightning detection were controversial due to the lack of time resolution of optical emissions that is needed to separate lightning from artificial or natural noise. Here we show the first high-time-resolution light curve of a transient optical phenomenon observed by the Lightning and Airglow Camera (LAC), a dedicated instrument on the Venus orbiter Akatsuki. The observed transient was 10 times brighter than a typical terrestrial lightning flash and had a duration of a few hundred milliseconds, whereas that of typical Earth lightning is only a millisecond. These characteristics are not typical, but are well within the variability of Earth lightning. An origin as a bolide flare cannot be excluded, but considering the expected occurrence frequency of meteoroids at Venus, is improbable. The low flash rate and long duration determined by the Akatsuki observation are not inconsistent with non-detection of lightning radio waves by the Cassini spacecraft.

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The Three-Dimensional Locating of VHF Broadband Lightning Interferometers

Atmosphere ◽

10.3390/atmos9080317 ◽

2018 ◽

Vol 9 (8) ◽

pp. 317 ◽

Cited By ~ 3

Author(s):

Hengyi Liu ◽

Shi Qiu ◽

Wansheng Dong

Keyword(s):

Time Resolution ◽

High Frequency ◽

Three Dimensional ◽

High Time Resolution ◽

Very High Frequency ◽

Time Difference Of Arrival ◽

Lightning Discharges ◽

Total Lightning ◽

Locating Information ◽

Very High

VHF (Very High Frequency) lightning interferometers can locate and observe lightning discharges with a high time resolution. Especially the appearance of continuous interferometers makes the 2-D location of interferometers further improve in time resolution and completeness. However, there is uncertainty in the conclusion obtained by simply analyzing the 2-D locating information. Without the support of other 3-D total lightning locating networks, the 2-station interferometer becomes an option to obtain 3-D information. This paper introduces a 3-D lightning location method of a 2-station broadband interferometer, which uses the theodolite wind measurement method for reference, and gives the simulation results of the location accuracy. Finally, using the multi-baseline continuous 2-D locating method and the 3-D locating method, the locating results of one intra-cloud flash and the statistical results of the initiation heights of 61 cloud-to-ground flashes and 80 intra-cloud flashes are given. The results show that the two-station interferometer has high observation accuracy on both sides of the connection between the two sites. The locating accuracy will deteriorate as the distance between the radiation source and the two stations increases or the height decreases. The actual locating results are similar to those of the existing VHF TDOA (Time Difference of Arrival) lightning locating network.

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LINETGIS analysis of lightning flash density in Serbia based on ten years data

Serbian Journal of Electrical Engineering ◽

10.2298/sjee1802201j ◽

2018 ◽

Vol 15 (2) ◽

pp. 201-211

Author(s):

Vesna Javor ◽

Leonid Stoimenov ◽

Nikola Dzakovic ◽

Nikola Dinkic ◽

Dario Javor ◽

...

Keyword(s):

Geographical Information ◽

Short Time Scale ◽

Lightning Flash ◽

Gis Technology ◽

Software Application ◽

Density Maps ◽

Covered Area ◽

Lightning Detection ◽

Lightning Discharges ◽

Short Time

Lightning detection networks installed throughout the world provide data for obtaining flash density maps and information about lightning discharges characteristics. According to the IEC 62858 Standard, lightning data for at least ten years is required to ensure that short time scale variations in lightning parameters are accounted for. LINET (European Lightning Detection Network) was installed in Serbia in 2008, so its data for the last ten years period are used for the analysis in this paper. LINETGIS is a new software application based on geographical information system (GIS) technology in order to obtain regional flash density maps of Serbia. LINETGIS application may be used for up-to-date regional flash density maps of Serbia, but also for any other GIS covered area.

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Two-colour observations of spikes and flares by high time resolution

Symposium - International Astronomical Union ◽

10.1017/s0074180900187364 ◽

1990 ◽

Vol 137 ◽

pp. 33-34

Author(s):

V.P. Zalinian ◽

A.A. Karapetian ◽

H.M. Tovmassian

Keyword(s):

Time Resolution ◽

High Time ◽

High Time Resolution ◽

Long Duration ◽

Flare Stars ◽

Ev Lac

Observations of flare stars with high time resolution permit to register spiky type flares and also to study in detail bright curves of flares. In Byurakan observatory observations of EV Lac have been made with 0.1 s time resolution simultaneouslyin two filters “U” and “B” [1-3]. These observations permited to detect flares of a burst type (Fig.1) and also to reveil multipeak structure of long duration flares. It is necessary to stress that simultaneous observations in two colours increas appresiably the thrustworthiness of the registered spiky flares.

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Flare Stars in Stellar Aggregates

International Astronomical Union Colloquium ◽

10.1017/s0252921100069244 ◽

1977 ◽

Vol 42 ◽

pp. 106-119

Author(s):

L.V. Mirzoyan

Keyword(s):

Time Resolution ◽

Physical Nature ◽

High Time ◽

Optical Observations ◽

Evolutionary Significance ◽

High Time Resolution ◽

Radio Observations ◽

Stellar Flares ◽

Flare Stars

After the report on flare stars presented by Ambartsumian and the author (1971) at the last Bamberg Colloquium, some success has been achieved in the study of these interesting objects.Optical observations of stellar flares with high time-resolution undoubtedly proved the explosive character of this phenomenon and the non-thermal nature of the radiation that appears at least at the beginning of the flare. Parallel optical and radio observations of flares in stellar aggregates complicated the interpretation and showed how far we are from an understanding of the physical nature of this phenomenon. Finally, new optical observations of stellar flares in aggregates of different age confirmed the evolutionary significance of this stage in the life of a star and led to the study of certain regularities in the evolution of flare stars.

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Megaflashes: Just How Long Can a Lightning Discharge Get?

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-19-0033.1 ◽

2019 ◽

Vol 101 (1) ◽

pp. E73-E86 ◽

Cited By ~ 5

Author(s):

Walter A. Lyons ◽

Eric C. Bruning ◽

Tom A. Warner ◽

Donald R. MacGorman ◽

Samantha Edgington ◽

...

Keyword(s):

Lightning Discharge ◽

Convective System ◽

Lightning Flash ◽

Additional Tool ◽

Convective Systems ◽

Lightning Detection ◽

Central United States ◽

Mesoscale Convective ◽

Lightning Discharges ◽

Mapping Arrays

Abstract The existence of mesoscale lightning discharges on the order of 100 km in length has been known since the radar-based findings of Ligda in the mid-1950s. However, it took the discovery of sprites in 1989 to direct significant attention to horizontally extensive “megaflashes” within mesoscale convective systems (MCSs). More recently, 3D Lightning Mapping Arrays (LMAs) have documented sprite-initiating lightning discharges traversing several hundred kilometers. One such event in a 2007 Oklahoma MCS having an LMA-derived length of 321 km, has been certified by the WMO as the longest officially documented lightning flash. The new Geostationary Lightning Mapper (GLM) sensor on GOES-16/17 now provides an additional tool suited to investigating mesoscale lightning. On 22 October 2017, a quasi-linear convective system moved through the central United States. At 0513 UTC, the GLM indicated a lightning discharge originated in northern Texas, propagated north-northeast across Oklahoma, fortuitously traversed the Oklahoma LMA (OKLMA), and finally terminated in southeastern Kansas. This event is explored using the OKLMA, the National Lightning Detection Network (NLDN), and the GLM. The NLDN reported 17 positive cloud-to-ground flashes (+CGs), 23 negative CGs (−CGs), and 37 intracloud flashes (ICs) associated with this massive discharge, including two +CGs capable of inducing sprites, with others triggering upward lightning from tall towers. Combining all available data confirms the megaflash, which illuminated 67,845 km2, was at least 500 km long, greatly exceeding the current official record flash length. Yet even these values are being superseded as GLM data are further explored, revealing that such vast discharges may not be all that uncommon.

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Solar Corona Investigation by the Coronal Line Photometer at Lomnický Peak

International Astronomical Union Colloquium ◽

10.1017/s0252921100025744 ◽

1994 ◽

Vol 144 ◽

pp. 431-434

Author(s):

M. Minarovjech ◽

M. Rybanský

Keyword(s):

Solar Corona ◽

Time Resolution ◽

Active Regions ◽

High Time ◽

High Time Resolution ◽

List Type ◽

Type Number ◽

Coronal Line ◽

Global Cycle

AbstractThis paper deals with a possibility to use the ground-based method of observation in order to solve basic problems connected with the solar corona research. Namely:1.heating of the solar corona2.course of the global cycle in the corona3.rotation of the solar corona and development of active regions.There is stressed a possibility of high-time resolution of the coronal line photometer at Lomnický Peak coronal station, and use of the latter to obtain crucial observations.

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Periodic Variations in the Coronal Green Line Intensity and their Connection with the White-light Coronal Structures

International Astronomical Union Colloquium ◽

10.1017/s0252921100064484 ◽

2000 ◽

Vol 179 ◽

pp. 197-200

Author(s):

Milan Minarovjech ◽

Milan Rybanský ◽

Vojtech Rušin

Keyword(s):

Time Resolution ◽

White Light ◽

Short Time Scale ◽

High Time Resolution ◽

Green Line ◽

Periodic Intensity ◽

Coronal Green Line ◽

Significant Intensity ◽

Short Time ◽

Coronal Structures

AbstractWe present an analysis of short time-scale intensity variations in the coronal green line as obtained with high time resolution observations. The observed data can be divided into two groups. The first one shows periodic intensity variations with a period of 5 min. the second one does not show any significant intensity variations. We studied the relation between regions of coronal intensity oscillations and the shape of white-light coronal structures. We found that the coronal green-line oscillations occur mainly in regions where open white-light coronal structures are located.

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