Related Experiment Video
Updated: Jun 25, 2026

Quantifying Mixing using Magnetic Resonance Imaging
Published on: January 25, 2012
Theory of strong intrinsic mixing of particle suspensions in vortex magnetic fields
1Sandia National Laboratories, Albuquerque, New Mexico 87185-1421, USA.
Abstract:
Recent experiments have shown that a type of triaxial magnetic field we call a vortex field can induce strong mixing in a magnetic particle suspension. A vortex triaxial field consists of a rotating magnetic field in a horizontal plane, with a dc field applied normal to this. The mixing torque is found to be independent of the field frequency and fluid viscosity over a broad range; scales as the square of the applied field; and is strongest for a balanced triaxial field-one in which the root-mean-square amplitudes of the three field components are equal. In this paper we show that these anomalous effects are consistent with the formation of volatile particle chains that have a precessionlike motion. Theoretical results are given for both particle chains and magnetic rods for arbitrary vortex field angles. A key conclusion is that the mixing torque is independent of particle size, making this mixing technique scale adaptive, and thus suitable for microfluidics applications.
Related Concept Videos
Magnetic Fields
A magnetic field is defined by the force that a charged particle experiences...
Theory of Strong Electrolytes
Potential Due to a Magnetized Object
The vector...
The Thermodynamics of Mixing
Motion Of A Charged Particle In A Magnetic Field
Magnetic Field due to Moving Charges
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...

