Formation of hexagonal pattern of ferrofluid in magnetic field

•We use FEM to investigate ferrofluid pattern formation in real space and real time.•We study the behavior of ferrofluid in a large area instead of a single peak.•A consistent mechanism is proposed to explain the behavior of pattern formation.

Simulation of hexagonal pattern formation of ferrofluid in magnetic field has been performed using a finite element method. Based on simulation result, a new mechanism involving ‘active rings’ is proposed to explain the generation of new peaks. Hexagonal nature of the pattern is shown to be originated from the intersections of these active rings. Evidence of this active ring mechanism is demonstrated and visualized with patterns grown in strong magnetic field. Calculated single peak profile also agrees well with experimental measurements.