MISTE Team Completes Theoretical Analysis of 3He Liquid-Gas Critical Point Measurements

The Microgravity Scaling Theory Experiment (MISTE) team was able to fit their measured susceptibility and specific heat data in the crossover region of the liquid-gas critical point of 3He to the theoretical model developed by Dr. Volker Dohm. The crossover region near a critical point is the part of parameter space where the fluid's thermodynamic properties change from the normal behavior expected from classical atomic theory of a fluid to the anomalous behavior characteristic of a critical point. Only two non-universal fitting parameters were needed to fit the susceptibility measurements. Three additional analytic background parameters were included to fit the specific heat data. The simultaneous fit of the susceptibility and specific heat measurements agreed very well with the experimental data both above and below the critical temperature. This analysis of the ground-based data will support the planning of the MISTE flight experiment. Dr. Fang Zhong of JPL presented these results at the APS March Meeting in Seattle on March 15, 2001.