A team of US researchers has finally worked out how reproduce ball lightning—sometimes referred to as St. Elmo's fire—in the lab.
Scientists from US Air Force Academy in Colorado have developed a new technique which allows them to generate clouds of plasma which float in the air for nearly half a second. Such clouds of lightning appear naturally in our skies, but are rare enough that they've been difficult to study and replicate until now.
It's claimed that Nikola Tesla made ball lightning in his Colorado Springs lab in either 1899 or 1900, but there's no evidence on record to suggest he did actually manage it. Now, though, the researchers have described a process which allows them to produce a "glow discharge" of plasma—a charged gas—above an electrolyte solution. Dr Lindsay, one of the researchers, explained to the BBC:
"[T]he initial stages of the electrical discharge that produce this 'plasmoid' have many similarities to lightning. They're just electric arcs - in this case, electric arcs to the surface of this solution of electrolytes. And then what happens is this plasmoid emerges from it."
By playing around with the electrolytic solution and recording experiments using high-speed cameras, the researchers have found that they're able to produce longer-lasting balls by varying the acidity. The results are published in the Journal of Physical Chemistry.
While the work has allowed the team to analyse the clouds of plasma and investigate their composition, work still needs to be undertaken to establish if this is the exact mechanism which leads to ball lightning, or whether it just produces a similar end result. Either way, labs around the world will no doubt soon be full of balls of St Emlo's fire—because, why not? [Journal of Physical Chemistry via BBC]
Image by Joe Thomissen under Creative Commons license