DYNAMICS OF MONOPOLE ANNIHILATION BY TYPE-1 2 STRINGS IN A NEMATIC LIQUID-CRYSTAL/

In uniaxial nematic liquid crystals, monopoles can be annihilated by t ype-1/2 strings. We present experimental measurements on the dynamics of this process as well as others, including loop collapses and monopo le-pair annihilations. On dimensional grounds one expects the size of a collapsing structure in a nematic liquid crystal to scale as tau(1/2 ) where tau is the time to annihilation. Indeed, type-1/2 loops and mo nopole-antimonopole pairs exhibit this kind of behavior. In contrast, for monopole annihilation by a type-(1/2) string we find that the stri ng-monopole separation scales as tau(alpha) where alpha = 0.629+/-0.00 6.