[Laser] Atmospheric turbulence bubbles

[Karel Kulhavy]

> 
>   The  areas of each aperture actually MULTIPLY to provide final optical
>   gain  and  transfer  of power - and the turbulence disruptions I named
>   'bubbles'  (for  want of a better expression) would probably better be
>   called  waves  or zones. They are very atmospheric condition dependent
>   and  path  dependent.  In  small apertures, the fading rate can run as
>   high  as 500 Hz in bad conditions, but lowers in frequency and reduces
>   in  fade depth as the aperture is increased. See the BSTJ article 1983
>   for practical examples and proof... I find that these atmospheric turb
>   disruptions are  a  problem  here in sunny Australia for any path over
>   about  6  km,  particularly  across  metropolitan (built-up) areas. If
>   you're  shooting  your beams over chimneys while the house occupant is
>   operating an open fire, you get a worst case scenario!

However on my 250m link there was a chimney in the middle and the beam
was obviously visibly going through the smoke. No packetloss was observed.

CL<