Experiments on the angular dependence of the thermomagnetic pressure difference

In a rectangular box containing a rarefied polyatomic gas, the combination of a temperature gradient, ▿T, and an external magnetic field, H, causes a slip of the molecules along the wall. This slip creates a pressure difference across the box, the “thermomagnetic pressure difference”. The phenomenon gives information on the behavior of angular momentum dependent polarizations near a boundary. Experimental results for this effect are presented as a function of the angle between ▿T and H for CO, N2, CH4, CF4, CO2, HD, SF6, CH3F and NH3. The results are analyzed in terms of a theory developed by Vestner, and numbers are obtained for three parameters which characterize the behavior of nonequilibrium polarizations for rotating molecules near a boundary.