Statics and dynamics of a critical binary fluid in a porous medium

We present small-angle neutron-scattering measurements of the static structure factor S(q) of the binary fluid mixture water-lutidine imbibed into the porous glass Vycor as a function of temperature and composition. S(q) changes from a Lorentzian in the one-phase region to a Lorentzian squared at the random-field transition. We relate the correlation lengths (9 {}{}{ξ}{}52 {}) to the previously measured relaxation times and find finite-size and random-field effects.