Abstract
Heat is transferred in superfluid He-4 via a process known as thermal counterflow. It has been known for many years that above a critical heat current the superfluid component in this counterflow becomes turbulent. It has been suspected that the normal-fluid component may become turbulent as well, but experimental verification is difficult without a technique for visualizing the flow. Here we report a series of visualization studies on the normal-fluid component in a thermal counterflow performed by imaging the motion of seeded metastable helium molecules using a laser-induced-fluorescence technique. We present evidence that the flow of the normal fluid is indeed turbulent at relatively large velocities. Thermal counterflow in which both components are turbulent presents us with a theoretically challenging type of turbulent behavior that is new to physics.
Original language | English |
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Article number | 045301 |
Pages (from-to) | 045301 |
Number of pages | 1 |
Journal | Physical Review Letters |
Volume | 105 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1 Jul 2010 |