Discovery of frequent lightning discharges in clouds on Venus

Ксанфомалити, Л. В.

doi:10.1038/284244a0

Cited by 47 publications

(25 citation statements)

References 2 publications

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“…7. Ksanfomality et al (1979) and Ksanfomality (1980) claim that some of the detected bursts showed a periodicity commensurate with the slow rotation of the Venera 11 lander during the latter part of the descent, consistent with spin modulation due to the directionality of the antenna as it swept past a distant (i.e., of small extent in azimuth) source. However, this suggestion does not seem quite consistent with the measurements of the probe rotation from angular velocity sensors (~7°/s-see Fig.…”

Section: Veneras 11-14 Lander Electromagnetic Observationsmentioning

confidence: 96%

Lightning detection on Venus: a critical review

Lorenz

2018

Prog Earth Planet Sci

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Claimed detections and nondetections of lightning and related electromagnetic emissions on Venus are qualitatively contradictory. Here, motivated by the commencement of observations by the Akatsuki spacecraft and by studies of future missions, we critically review spacecraft and ground-based observations of the past 40 years, in an attempt to reconcile the discordant reports with a minimal number of assumptions. These include invoking alternative interpretations of individual reports, guided by sensitivity thresholds, controls, and other objective benchmarks of observation integrity. The most compelling evidence is in fact the first, the very low frequency (VLF) radio emissions recorded beneath the clouds by all four of the Veneras 11-13 landers, and those data are re-examined closely, finding power-law amplitude characteristics and substantial differences between the different profiles. It is concluded that some kind of frequent electrical activity is supported by the preponderance of observations, but optical emissions are not consistent with terrestrial levels of activity. Venus' activity may, like Earth's, have strong temporal and/or spatial variability, which coupled with the relatively short accumulated observation time for optical measurements, can lead to qualitative discrepancies between observation reports. We note a number of previously unconsidered observations and outline some considerations for future observations.

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Section: Veneras 11-14 Lander Electromagnetic Observationsmentioning

confidence: 96%

Lightning detection on Venus: a critical review

Lorenz

2018

Prog Earth Planet Sci

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“…Venera 11 and 12 landers: The Venera 11 and 12 probes descended onto Venus in 1978, at similar midday, low latitude locations (Ksanfomality 1980). Each lander carried a high sensitivity loop antenna detector with four narrowband channels centered at 10, 18, 36, and 89 kHz, a wideband signal (8-90 kHz) detector, and an impulse counter.…”

Section: Electromagnetic Wave Observationsmentioning

confidence: 99%

Lightning Detection by LAC Onboard the Japanese Venus Climate Orbiter, Planet-C

et al. 2008

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Lightning activity in Venus has been a mystery for a long period, although many studies based on observations both by spacecraft and by ground-based telescope have been carried out. This situation may be attributed to the ambiguity of these evidential measurements. In order to conclude this controversial subject, we are developing a new type of lightning detector, LAC (Lightning and Airglow Camera), which will be onboard Planet-C (Venus Climate Orbiter: VCO). Planet-C will be launched in 2010 by JAXA. To distinguish an optical lightning flash from other pulsing noises, high-speed sampling at 50 kHz for each pixel, that enables us to investigate the time variation of each lightning flash phenomenon, is adopted. On the other hand, spatial resolution is not the first priority. For this purpose we developed a new type of APD (avalanche photo diode) array with a format of 8 × 8. A narrow band interference filter at wavelength of 777.4 nm (OI), which is the expected lightning color based on laboratory discharge experiment, is chosen for lightning measurement. LAC detects lightning flash with an optical intensity of average of Earth's lightning or less at a distance of 3 Rv. In this paper, firstly we describe the background of the Venus lightning study to locate our spacecraft project, and then introduce the mission details.

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“…Various features of 100 Hz signals led TAYLOR et al (1979) and SCARF et al (1980) to find a close resemblance with the earlier in situ measurement of electromagnetic noise using Venera-11 lander which were attributed to Venus lightning (KSANFOMALITY, 1979(KSANFOMALITY, , 1980. Since PVO does not descend below about 140 km, 100 Hz signal was considered to propagate upwards along the nightside wake region magnetic field in whistler mode.…”

Section: Introductionmentioning

confidence: 99%

“…With the present state of data availability, it is not all possible to pin down the problem of lightning generation. However, the Venera lander (KSANFOMALITY et al, 1983) and PVO data SINGH and RUSSELL, …”

Section: Detailed Features Of Waveguide Boundaries and Wave Generationmentioning

confidence: 99%

Role of the Mode Theory on Lightning Generated Waves Propagating in Venus-Ionosphere Waveguide.

Singh

Upadhyay

1993

J. geomagn. geoelec

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The wave mode either electromagnetic or electrostatic of the OEFD measured signals is unknown and needs to be ascertained by indirect means. Considering these waves to be generated by global Venus lightning, the wave attenuation along the Venus-ionosphere wave-guide has been computed. The effective wave attenuation versus frequency shows a "knee" characterizing minimum attenuation 6 kHz. This "knee" is consistent with the amplitude spectral peak of OEFD signals around this frequency. This feature of the OEFD signals implies that the Venus lightning may have global occurrence. The lightning generated signals may travel considerable distance within the Venus-ionosphere waveguide. The encounter of these signals with plasma "holes" or ion "troughs" in the nightside of Venus wake region results in the leakage of the signals out of the shielding ionosphere. These signals are occasionally recorded by the OEFD. The occurrence rate statistics shows that the leakage of 5.4 kHz signals through the plasma "holes" in the vicinity of PVO periapsis are most effective. The maximum occurrence rate of higher frequency signals change in altitude slightly from one PVO season to another.

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Discovery of frequent lightning discharges in clouds on Venus

Cited by 47 publications

References 2 publications

Lightning detection on Venus: a critical review

Lightning detection on Venus: a critical review

Lightning Detection by LAC Onboard the Japanese Venus Climate Orbiter, Planet-C

Role of the Mode Theory on Lightning Generated Waves Propagating in Venus-Ionosphere Waveguide.

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