Experimental investigation of the thermomagnetic force in N2, CO, and NH3 gases at 300°K

Abstract

The thermomagnetic force is observed as a magnetic field induced change in the thermal force exerted on an object suspended in a heat-conducting rarefied polyatomic gas. A recently developed extremely sensitive stress measuring technique and higher magnetic fields have permitted the experimental investigation of the thermomagnetic force to saturation levels in the gases N2, CO, and NH3 at 300°K. We have studied the force effects for three well-defined temperature fields produced by isothermal boundaries with different geometry. The increased accuracy of the experimental results has permitted the fit of the data to a typical saturation curve. From this curve saturation values and the position on the H/p axis at which the effect reaches half-magnitude (H/p)1/2 values have been determined for the various gases under different conditions of temperature field and pressure. A comparison is made with the Senftleben–Beenakker thermal conductivity effects.