Creating clay lightning in the laboratory

Lightning lightning - glowing fireballs that slowly move mysteriously often appear in thunderstorms - were created in the laboratory of Max Planck Institute for Plasma Physics, Germany.

Researchers from the Max Planck Institute and Humboldt University in Berlin took advantage of the phenomenon of underwater discharge to create brilliant plasma clouds similar to rock lightning, which lasted nearly half a second and had a diameter of up to 20 centimeters. .

Despite the flashiness, these fireballs seemed to be quite cold, not igniting paper.( Photo: Max Planck Institute for Plasma Physics )

They hope these artificial entities will help to understand the strange phenomenon and perhaps open new light on the use of hot plasma for fusion power plants.

Claystone has been a headache for scientists for centuries. Although the data about them is very small, there are many anecdotes about this phenomenon, with well-known witnesses like Charlemagne, Henry II and physicist Niels Bohr.

Most descriptions say that lightning strikes in the air are quite slow, equal to the speed of the runner, which lasts for a few seconds and in rare cases can take minutes. Its path coincides with the wind direction. Sometimes the fireball seems to stop completely. When he moved, he could hear a squeak or a squeak. The color of the clay rock is very different: It is seen that there are bright red and yellow spheres, both vivid white and dark green. What about size? Usually clay is not bigger than 20 cm in diameter.

Many scientists believe that lightning is a plasma ball formed when lightning strikes the ground, but its real mechanism is still a mystery despite many hypotheses.

Earlier this year, Israeli scientists created plasma spheres using microwaves to vaporize different materials, but Gerd Fussmann and Max Institute's colleagues used another technique they believed. that is closer to the natural phenomenon.

" It is possible that lightning bolts have interacted with water to create lightning, " Fussmann said. " So we use a fast discharge, with a voltage as high as 5,000 volts to evaporate some of the water. glass tank and create plasma ball ".

This glass tank contains two electrodes, one of which is isolated from the surrounding water by a clay tube. High voltage will produce huge currents of up to 60 amps - 200 times larger than the line needed to lethal - run through the water for a fraction of a second. This current flows into the clay tube, causing the water to evaporate and a brilliant plasma ball - made up of ionized water molecules - will float off the surface.

"This sphere exists up to 0.3 seconds after the current is turned off - much longer than regular plasma, which disintegrates very quickly," Fussmann said. Plasma is used in laboratories and fusion plants often decompose within milliseconds after the power is turned off.

Although glowing brightly, the balls seemed to be quite cold, very similar to neon lights. A sheet of paper above them was lifted but did not catch fire.

Fussmann is currently testing the spectrum emitted from the light of these fireballs, and is expected to find out if their size and life span are affected by the magnitude of the current.

To determine exactly what happens when lightning strikes appear in nature, he hopes to compare the characteristics of artificial "lightning" with the existing theories about their birth.

T. An