High Rayleigh Number Thermal Convection

This paper considers the manner in which low temperature helium gas is used to generate turbulent convection, reviews the lessons learned so far, and finally suggests a possible experiment that draws upon these lessons and should yield unambiguous resugts. The proposed apparatus would be relatively tall (5 m sample height), have a sample diameter-to-height aspect ratio of 2/3, and be able to achieve Rayleigh numbers exceeding 1015 under rigorous ideal gas conditions.