Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gamma-ray cloudbursts shed light on lightning

15.02.2008
High-energy gamma rays from thunderclouds may help us to predict when lightning will strike

A team including researchers at RIKEN’s Discovery Research Institute in Wako and the University of Tokyo has observed a burst of high-energy gamma radiation emerging from a thundercloud over the Sea of Japan (1). The discovery could help to reveal the complex electrical processes that cause lightning.

“Free electrons, originally produced by cosmic rays, can be accelerated by the strong electric fields in thunderclouds,” explains project scientist Harufumi Tsuchiya. “If they reach relativistic energies, they can knock other electrons out of their atoms, causing a ‘runaway electron avalanche’.”

When one of the high-energy electrons is deflected by the nucleus of an atom, it loses energy in the form of gamma rays called Bremsstrahlung—literally ‘braking radiation’. Bursts of these gamma rays have been detected by near-Earth satellites above thunderclouds, and very short bursts are often recorded near the ground. Longer bursts lasting up to a few minutes appear to be very rare events, and physicists are unsure where they come from or what they consist of.

To answer these questions, the researchers built new radiation detectors based on devices on board the Suzaku cosmic x-ray satellite. The detectors were installed on the roof of the Kashiwazaki–Kariwa nuclear power plant in Niigata. On 6 January 2007, during a violent winter thunderstorm, they recorded a large radiation spike lasting over a minute, which could not be attributed to background radiation or electrical noise.

The spectrum of radiation included high-energy gamma rays that could not have been produced by thermal processes—which would require temperatures of billions of degrees Celsius. Therefore the burst must have been caused by Bremsstrahlung processes.

The burst was recorded approximately 70 seconds before a large flash of lightning, leading the researchers to speculate on whether the two events are related. In theory the runaway electrons could produce a large number of slower electrons, leading to electrical imbalance and lightning. “If thunderclouds frequently generate gamma ray bursts prior to lightning discharges, detailed observations of such rays would allow us to predict when lightning will occur,” claims Tsuchiya.

However, more observations are needed to prove such a link. “We believe the burst behaves like a searchlight beam, illuminating only a limited area on the ground,” says Tsuchiya, “so we were probably fortunate that the beam happened to pass over our detector.” To test this hypothesis, the researchers plan to spread several detectors over a large area, so that they might trace the movement of a gamma ray burst.

1. Tsuchiya, H., Enoto, T., Yamada, T., Yuasa, T., Kawaharada, M., Kitaguchi, T., Kokubun, M., Kato, H., Okano, M., Nakamura, S. & Makishima, K. Detection of high-energy gamma rays from winter thunderclouds. Physical Review Letters 99, 165002 (2007).

Saeko Okada | ResearchSEA
Further information:
http://www.researchsea.com
http://www.rikenresearch.riken.jp/research/380/image_1349.html

More articles from Physics and Astronomy:

nachricht Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>