MadSci Network: Physics

Re: Is it possible to generate an artificial

Date: Wed Sep 20 00:31:16 2000
Posted By: Richard Bersin, Other (pls. specify below), Senior Technical Staff Member, Emergent Technologies
Area of science: Physics
ID: 968476528.Ph

Dear James:
You ask about making low voltage lightning in the laboratory if you make a 
stream of ionized air.  The answer to your question depends a lot upon 
what you mean by "lightning".  Normally lightning refers to the natural 
phenomenon during a thunderstorm;  in that case extremely high voltages are 
generated between the clouds and the earth, and when the voltage is high 
enough (an electric field of 33,000 volts/centimeter breaks down the air 
into a lightnint bolt) then lightning occurs.  This lightning is like an 
arc discharge, which means the currents are very very high, and the light 
is very bright, and in a very short time the huge current drains away all 
the voltage and the lightning is over.  So regular lightning is a 
catastrophic phenomenon which starts suddenly when the air breaks down, and 
is over almost immediately because the charge is drained away by the very 
large currents.  If you have a path of ionized air already there, then it 
is possible if you apply the voltage very quickly so that the voltage 
builds up very high before the the current has time to drain it away there 
can be a breakdown of the air and a lightning bolt might be created at 
perhaps a somewhat lower voltage.

If by "lightning" you really mean a "spark", you could make a spark at very 
low voltage compared to real lightning (which is millions of volts!)by 
having ions in the air already;  however the spark would go out very 
quickly because the high current in the spark drains away the voltage just 
like lightning and it is over very quickly.  It would be really tiny 
compared to real lightning.  So the answer depends a lot on what you mean 
by your question!

R. Bersin

Current Queue | Current Queue for Physics | Physics archives

Try the links in the MadSci Library for more information on Physics.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-2000. All rights reserved.