A quasi-equilibrium analysis to predict the dependence of ferrofluid aggregate properties on field ramping rate

When a thin layer of ferrofluid is subjected to an external magnetic field, the particles clump together to form aggregates. These aggregates are approximately uniformly sized with uniform spacing. Recently, experimental results have shown how the ramping rate of the external field can change the aggregate spacing. We have developed an analytical model to predict how aggregate spacing changes as a function of ramping rate. This model is in good agreement with experimental results and provides insight into the dynamics of aggregate formation.