At 12:32 PM 2/11/2006, David Robbins K1TTT wrote:
>You are mixing up a couple things... 'cosmic rays from a strike' has nothing
>to do with how strokes occur. There is some evidence for very large strokes
>causing enough of a field to cause x-rays and maybe higher energy particles,
>but that is after the fact.
>The causing of strokes by cosmic rays is another thing all together. Even
>with assistance from cosmic rays there is not enough potential to bridge the
>gap from cloud to earth in one step. And if cosmic rays really did cause
>enough of an ion trail all the way from the cloud to the ground then the
>strokes would always be arrow straight, which obviously they aren't. the
>phenomena of leader progression and streamers is very well documented now
>and explains very nicely how the stroke channel grows in steps from the
>cloud or ground and how the final connection is made to start the discharge.
>This also works for strokes that progress a very long distance away from the
>cloud, no need for cosmic help in either case.
There is a new trail of research suggesting that cosmic rays help to trigger
the breakdown. Here is a note from wikipedia.org and a reference to a
Cosmic rays have been implicated in the triggering of electrical
breakdown in lightning. It has been proposed [see Gurevich and Zybin,
Physics Today, May 2005, "Runaway Breakdown and the Mysteries of
Lightning"] that essentially all lightning is triggered through a
relativistic process, "runaway breakdown", seeded by cosmic ray
secondaries. Subsequent development of the lightning discharge then
occurs through "conventional breakdown" mechanisms.
The reference for Keith is NOVA ScienceNOW and it aired OCT 18, 2005.
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