Study of Shock Waves and Phase Transition in He II by Using a Superfluid Shock Tube Facility

Abstract

In the experimental study, we focus on the thermo-fluid dynamics of shock waves and the lambda phase transition, He II to He I, induced by shock compression utilizing the newly developed superfluid shock tube facility. In the experimental facility, a compression shock wave is generated in He II by the impingement of a gas dynamic shock wave propagating through the helium vapor onto a He II free surface. He II can be shockcompressed to convert to He I across the lambda line in the case of He II initially at temperatures rather close to the lambda temperature. The highly transient lambda phase transition is detected very rapidly (a few μsec) by a superconductive temperature sensor, where the temperature variation is positive, in striking contrast to the temperature drop that occurs during He II shock compression without the lambda transition. Photographs of these phenomena are taken by the Schlieren visualization method.