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SUMMARY:When ices collide: electricity\, cosmogony\, and reciprocity - Joh
 n S. Wettlaufer\, Yale University
DTSTART:20081010T150000Z
DTEND:20081010T160000Z
UID:TALK14476@talks.cam.ac.uk
CONTACT:Raymond E. Goldstein
DESCRIPTION:In 1750 Benjamin Franklin proposed an experiment to demonstrat
 e the electrical basis of thunderstorm lightning by flying a kite into a s
 torm cloud thereby extracting sparks. The principle was demonstrated in 17
 52 by Dalibard who replaced the kite with a 12 meter metal rod\, launching
  international investigations into the nature of electricity which rather 
 quickly led to Franklin’s being awarded the Copley Medal of the Royal So
 ciety in 1753. Nearly 260 years later the study of thunderstorm electrific
 ation is no less active but is rather more focused. It has been understood
  from detailed field studies and simulations that active collisions betwee
 n ice particles underlies lightning but the microscopic mechanism of charg
 e separation requires a rather detailed understanding of\, inter- alia\, t
 he intrinsic quasi-steady electrodynamics of ions in ice\, surface physics
 \, and long ranged intermolecular forces. Such phenomena turn out to be im
 plicated in the agglomeration of matter during the formation of planetesim
 als in solar nebula\, the redistribution of particles in comets\, the tail
 oring of the properties of composite materials and Onsager reciprocity in 
 systems where the solvent is frozen.
LOCATION:MR2\, Centre for Mathematical Sciences\, Wilberforce Road\, Cambr
 idge
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