Uncovering the mysteries of ball lightning

“People have been pondering ball lightning for a couple of centuries,” says James Brian Mitchell, a scientist the University of Rennes in France. Mitchell says that different theories of how it forms, and why it burns in air, have been considered, but until now there were no experimental indications of what might be happening as part of the ball lightning phenomenon. Now, working with fellow Rennes scientist LeGarrec, as well as Dikhtyar and Jerby from Tel Aviv University and Sztucki and Narayanan at the European Synchrotron Radiation Facility in Grenoble, France, Mitchell can prove that nanoparticles likely exist in ball lightning. The results of the work by Mitchell and his colleagues can be found in Physical Review Letters: “Evidence for Nanoparticles in Microwave-Generated Fireballs Observed by Synchrotron X-Ray Scattering.” “A group in New Zealand came up with this idea of ‘dusty plasma,’” Mitchell tells PhysOrg.com. “They thought that nanoparticles burning in air could cause ball lightning to remain for seconds, rather than disappearing after milliseconds. This was an attractive model.” But the model couldn’t be proved without detecting the nanoparticles. Mitchell says that he saw a paper by Jerby describing the creation of a fireball in controlled conditions. “These fireballs floated in air,” Mitchell explains. “They resemble ball lightning.” This provided an opportunity to study whether or not nanoparticles were likely to exist in this natural phenomenon, shedding light on a scientific mystery.

The work was done at the European Synchrotron Radiation Facility in Grenoble. The facility uses an x-ray that is 10 billion times more powerful than a typical x-ray found in a hospital. Additionally, Mitchell explains, the accelerator for the synchrotron is more than a kilometer in circumference: “We can get measurements here that we couldn’t get in many other places.” “We passed an x-ray beam through the fireball we made, and saw that it was scattered. - continued on unexplained mysteries