Heat transfer in water was visually investigated using a liquid-crystal sheet with thermochromism in a hybrid magnet. Upward thermal convection was significantly suppressed by gradient magnetic fields, however, it remained even under magnetic levitation conditions with a gradient field of B(dB/dz) = -1360 T 2m -1. A thermal conduction state without convection was realized under a stronger gradient field of B(dB/dz) = -2880 T 2m -1 at 35-40°C, and surprisingly the downward magnetic convection was observed under the same field at 40-45°C. The temperature dependence of the magnetic susceptibility of water is responsible for the convection behavior in the gradient fields.
- Gradient magnetic field
- Magnetic convection
- Thermal convection
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering