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Kurt Stocklmeir wrote: I would like to know how much am and fm radio waves are made by lightning has any person tried this - when lightning is around use their radio to find how many watts of am and fm radio waves are made by lighning thank you for any answers I think you'll find that your question doesn't "map well" onto how lightning works. Saying "AM radio waves" or "FM radio waves" implies that there is a carrier wave, which is being either amplitude-modulated or frequency-modulated. Neither of these is the case for lightning strikes. Lightning consists of strong, irregular pulses of current with rapid rise times. Each pulse generates a broadband burst of electromagnetic energy, with energy content distributed widely across a whole range of frequencies. The figure I'm seeing is that a single lightning strike typically releases about 5 billion joules of energy (5 billion watt-seconds). Most of this is released in a very short period of time (under a millisecond). According to http://www.lightningsafety.com/nlsi_info/thunder2.html about 90% of the lighting's energy is released as heat, less than 1% is released as sound, and the rest (call it 10%) is released as light (and, I presume, other frequencies of electromagnetic energy). There's a very strong electromagnetic pulse near the lighting stroke and the earth impact point, due to the high current flow. In the "radio" frequencies per se (e.g. from a few hundred kHz to a few hundred MHz) it's probably a fraction of a percent of the total lightning strike energy... mostly in sharp bursts at the beginning (and perhaps end) of each individual sub-stroke. |
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