SIGNIFICANT EVENTS - SCIENCE EVENTS
05/02/03

DYNAMX and CQ Teams Find Novel Heat Conduction Modes

The Critical Dynamics in Microgravity (DYNAMX, or DX) Group at the University of New Mexico, along with the Heat Capacity Enhancement in Superfluid Helium Under a Heat Flux (CQ) Group at Caltech, have collaborated closely in two recent discoveries that are very important to the study of the quantum fluids: Self-organized heat transport in liquid helium near its superfluid transition was observed by the DYNAMX Group and reported in Physical Review Letters in 1997. Recently this collaboration has discovered a new temperature-entropy wave that propagates only against the heat flux direction on this self-organized state. Although a similar new wave mode had been predicted by Weichman and Miller three years ago, this newly observed mode propagates over a much wider range of heat flux than had been predicted. This remarkable result provides an advance in our understanding of the quantum fluids, and it provides an indication of an important new collective behavior that may be important in many other physical and biological systems that exhibit active transport. These results will be published soon in Physica B, as part of the proceedings of LT23. In the same series of experiments, this DX and CQ collaboration has observed a much larger superfluid helium thermal gradient in their heat-from-above measurements just before the onset of the self-organized heat transport state than had been observed in heat-from-below measurements by Baddar et al. These results suggest that the superfluid thermal gradient observed on orbit may be much larger than that measured on Earth, as has been predicted by theorists. These new superfluid gradient data are also being prepared for publication.