Laser triggers electrical activity in thunderstorm for the first time

During the tests, the research team quantified the electrical activity in the clouds after discharging laser pulses. Statistical analysis showed that their laser pulses indeed enhanced the electrical activity in the thundercloud where it was aimed—in effect they generated small local discharges located at the position of the plasma channels.

The limitation of the experiment, though, was that they could not generate plasma channels that lived long enough to conduct lightning all the way to the ground. The plasma channels dissipated before the lightning could travel more than a few meters along them. The team is currently looking to increase the power of the laser pulses by a factor of 10 and use bursts of pulses to generate the plasmas much more efficiently.

Lightning strikes have been the subject of scientific investigation dating back to the time of Benjamin Franklin, but despite this, remain not fully understood. Although scientists have been able to trigger lightning strikes since the 1970s by shooting small rockets into thunderclouds that spool long wires connected to the ground, typically only 50 percent of rocket launches actually trigger a lightning strike. The use of laser technology would make the process quicker, more efficient and cost-effective and would be expected to open a number of new applications.

Kasparian conducted the research with his colleagues at CNRS, the University of Lyon, the University of Geneva, École Polytechnique and ENSTA in Palaiseau, France, the Free University of Berlin and the Dresden-Rossendorf Research Center as part of the Teramobile project. This work was funded jointly by the CNRS, DFG, the French and German ministries of foreign affairs, Agence Nationale de la Recherche, Fonds national suisse de la recherche scientifique, and the Swiss Secrétariat d'État à l'Éducation et à la Recherche.

Paper: "Electric events synchronized with laser filaments in thunderclouds," Jérôme Kasparian et al, Optics Express, Vol. 16, Issue 8, April 14, 2008, pp. 5757-63; abstract at http://www.opticsexpress.org/abstract.cfm?id=157189.

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