'LEAPING SUNDOGS'
Produced by Storm Electrostatic Fields
W. Beaty 11/7/09
Years ago during museum exhibits work I was explaining rainbow optics
...and also explaining thunderstorm dynamics. I stumbled across a strange
idea: shouldn't the strong electrostatic fields in thunderstorms have a
visible
effect on rainbows? E-fields should slightly distort falling raindrops,
causing the light distribution of a rainbow to change slightly.
Sometimes we should
notice that a rainbow suddenly "flicks" during a lightning bolt, then
slowly changes to its initial pattern as the e-fields build before another
strike.
I just heard from LH and JB on youtube about three
videos apparently showing this in action! But it's not rainbows. Instead
it's suspended ice crystals or mist droplets condensing just above a
rising thunderhead, brightly back-lit by the sun. Take a look:
- http://www.youtube.com/watch?v=1IAGE9f0K1Q large leap
- http://www.youtube.com/watch?v=1Z_-uK5Btik small 'object'
- http://www.youtube.com/watch?v=Sc9Ks6H3coY Malaysia
- http://www.youtube.com/watch?v=cUcH3VClzUI small 'object' 2
Rather than distortions of droplets, perhaps these are
"sundogs" or
parhelia light patterns caused by aligned ice crystals. A changing
e-field could rotate all the ice plates or needles, causing the sundog to
suddenly change shape and position. Or less likely,
perhaps some condensing droplets are changing size under e-field
influence (growth/shrinkage of small droplets is known to be altered by
strong electrostatic fields.)
I just heard that relatively tiny e-field of 10V/mm will totally align
suspended ice crystals. Storm fields are far stronger, so "leaping
sundogs" should be quite common. See foster/hallett paper
via Google Scholar search.
