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Q & A: radio waves move plasma

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Most recent answer: 03/17/2012
Q:
can a vhf radio wave (144-148 mhz) cause the plasma in a plasma globe to actually move? at a radio club we witnessed that the plasma trails in the globe got brighter and appeared to move toward the antenna. did the radio waves cause the ions and atoms to move? i have been unable to find any definitive information. thanks!
- charles (age 61)
brooklyn, ny, usa
A:
Sure, there's a strong interaction between radio waves and conductive plasma. When I was young, we had loudspeakers with ionic tweeters. They had no moving diaphragm, just a little cloud of plasma created by an intense 25 MHz wave. Modulation of the 25 MHz intensity caused the cloud to grow and shrink, generating the high-frequency audio sound. I could pick up the signal  on the shortwave. You could even see a flicker when cymbals clashed. It was great except for the ozone fumes and  ultraviolet radiation from the plasma.

Mike W.

(published on 03/17/2012)

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