Double Rosensweig instability in a ferrofluid sandwich structure

TL;DR

This paper investigates the complex interplay of magnetic and interfacial instabilities in a ferrofluid sandwich structure under strong magnetic fields, analyzing pattern formation and critical conditions for layer disintegration.

Contribution

It provides a theoretical analysis of the double Rosensweig instability in a ferrofluid sandwich, including critical field estimates and pattern evolution insights.

Findings

Identification of conditions leading to interface instability

Estimation of critical magnetic field strength for layer breakup

Analysis of interfacial pattern evolution under magnetic influence

Abstract

We consider a horizontal ferrofluid layer sandwiched between two layers of immiscible non-magnetic fluids. In a sufficiently strong vertical magnetic field the flat interfaces between magnetic and non-magnetic fluids become unstable to the formation of peaks. We theoretically investigate the interplay between these two instabilities for different combinations of the parameters of the fluids and analyze the evolving interfacial patterns. We also estimate the critical magnetic field strength at which thin layers disintegrate into an ordered array of individual drops.