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SUMMARY:When ices collide: electricity\, cosmogony\, and reciprocity - Joh
 n S. Wettlaufer\, Yale University
DTSTART:20081010T150000Z
DTEND:20081010T160000Z
UID:TALK14463@talks.cam.ac.uk
CONTACT:Raymond E. Goldstein
DESCRIPTION:In 1750 Benjamin Franklin proposed an experiment to demonstrat
 e the\nelectrical basis of thunderstorm lightning by flying a kite into a\
 nstorm cloud thereby extracting sparks.   The principle was\ndemonstrated 
 in 1752 by Dalibard who replaced the kite with a 12\nmeter metal rod\, lau
 nching international investigations into the\nnature of electricity which 
 rather quickly led to Franklin's being\nawarded the Copley Medal of the Ro
 yal Society in 1753. Nearly 260\nyears later the study of thunderstorm ele
 ctrification is no less\nactive but is rather more focused.  It has been u
 nderstood from\ndetailed field studies and simulations that active collisi
 ons\nbetween  ice particles underlies lightning but the microscopic\nmecha
 nism of  charge separation requires a rather detailed\nunderstanding of\, 
 inter- alia\, the intrinsic quasi-steady\nelectrodynamics of ions in ice\,
   surface physics\, and long ranged\nintermolecular forces.  Such  phenome
 na turn out to be implicated in\nthe agglomeration of matter  during the f
 ormation of planetesimals in\nsolar nebula\, the  redistribution of partic
 les in comets\, the\ntailoring of the  properties of composite materials a
 nd Onsager\nreciprocity in systems  where the solvent is frozen.\n
LOCATION:MR2\, Centre for Mathematical Sciences\, Wilberforce Road\, Cambr
 idge
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