Characteristics of a Magnetic Bulk Thermostat for Granular Gas Investigations in Microgravity

A magnetic thermostat employing soft-ferromagnetic particles and a varying magnetic field has been developed to investigate a homogeneous granular gas system in microgravity. While the thermostat’s mechanism of creating homogeneous distribution of the particles was shown earlier, its characteristics have not been understood well due to limited access to a microgravity environment. Therefore, a parametric study by numerical simulation based on the discrete element method is carried out in this paper to evaluate effects of tunable parameters in the thermostat. The result shows the capability of the system and provides a wide range of options and improvements for future experiments. Moreover, it predicts that the thermostat allows variation of homogeneity and excitation level of the granular gas just by changing the magnetic parameters without using any mechanical means. In addition, the suggested improvement is experimentally implemented and evaluated in a drop tower test.