Lightning research sparks new discovery

Nov 01, 2005

Lightning, a high-voltage discharge that strikes quickly and sometimes fatally, is very difficult to study. A new and surprising finding by Florida Institute of Technology's Dr. Joseph Dwyer and his team brings the study of lightning research into the laboratory.

Already noted for his discoveries related to x-ray emission from natural and triggered lightning, Dwyer, an associate professor of physics and space sciences, conducted a related experiment recently. He was shocked to find that laboratory-generated sparks make x-rays, too.

"We know that x-rays are made in outer space--in exotic places like the center of the sun and supernovae--but we didn't think they could be made so easily in the air," said Dwyer. "The results should allow for the detailed laboratory study of runaway breakdown, a mechanism that may play a role in thunderstorm electrification, lightning initiation and propagation, and terrestrial gamma-ray flashes."

High voltage sparks are a ubiquitous phenomenon in nature. They occur in a wide range of settings, from a finger touching a doorknob to the massive lightning flashes on Jupiter. Until Dwyer's discovery, it was believed that such electrical discharges involved only low-energy electrons, not the kind of high-energy electrons that make x-rays.

To conduct their recent experiment, Dwyer and his team; Florida Tech professor of physics and space sciences, Dr. Hamid Rassoul; Florida Tech graduate student Zaid Saleh and University of Florida graduate student Jason Jerauld, brought the instruments they had used to study lightning in Florida to Lightning Technologies Inc., in Pittsfield, Mass. They set up the equipment next to a Marx spark generator just to see what would happen. Half the team guessed they would see x-rays, half did not.

What they found was that 14 tests of 1.5- 2.0 million-volt sparks in the air produced x-ray bursts. The bursts were remarkably similar to the x-ray bursts previously observed from lightning.

"This amazed us. It opens the door to answering really big questions about lightning by generating it in the lab," said Rassoul. "It also tells us that we have a lot to learn about how even small sparks work."

Dwyer is excited about the opportunity to study the poorly understood phenomenon of runaway breakdown--shown to be associated with lightning--in the lab. To date, the only mechanism that can account for the creation of the high-energy electrons that make x-rays is the runaway breakdown of air. In this phenomenon, the electric force experienced by electrons exceeds the effective frictional force due to collisions with air molecules, allowing the electrons to "run away" and gain very large energies.

The new finding, published in October in Geophysical Research Letters, will also be discussed on Nature online, the first week of November.

Source: Florida Institute of Technology

Explore further: UCI team is first to capture motion of single molecule in real time

add to favorites email to friend print save as pdf

Related Stories

New laser technology could divert lightning strikes

Apr 01, 2014

(Phys.org) —Optical scientists at the University of Arizona and the University of Central Florida have developed a technology capable of sending high-intensity laser beams through the atmosphere much farther ...

Change in geometry improves aerodynamics

Dec 23, 2013

Kids and dogs understand the force of air, when they stick their hands and heads out of moving cars only to feel them pushed back. It may be invisible, but air is like a see-through net dragging a vehicle back as it strains ...

Recommended for you

And so they beat on, flagella against the cantilever

14 hours ago

A team of researchers at Boston University and Stanford University School of Medicine has developed a new model to study the motion patterns of bacteria in real time and to determine how these motions relate ...

Tandem microwave destroys hazmat, disinfects

18 hours ago

Dangerous materials can be destroyed, bacteria spores can be disinfected, and information can be collected that reveals the country of origin of radiological isotopes - all of this due to a commercial microwave ...

Physicists design zero-friction quantum engine

18 hours ago

(Phys.org) —In real physical processes, some energy is always lost any time work is produced. The lost energy almost always occurs due to friction, especially in processes that involve mechanical motion. ...

Cornell theorists continue the search for supersymmetry

20 hours ago

(Phys.org) —It was a breakthrough with profound implications for the world as we know it: the Higgs boson, the elementary particle that gives all other particles their mass, discovered at the Large Hadron ...

User comments : 0