Investigating Pure Quantum Turbulence in Superfluid 3He and a Means of Directly Inferring the Turbulent Energy Content
Seminar Room 1, Newton Institute
The lack of a general solution to the governing Navier-Stokes equations means that there is no fundamental theory of turbulence. Simpler pure quantum turbulence, the tangle of identical singly-quantized vortices in superfluids at T~0 may provide a deeper understanding of turbulence in general. In the present context this is especially relevant to the measurement of the turbulent energy. While the well-known Kolmogorov theory predicts the energy distribution of turbulence and how it decays, in normal systems the turbulent energy is generally only a small perturbation on the total thermal energy of the supporting medium. In quantum turbulence, however, the turbulent energy is accessible. A stationary condensate is necessarily in its ground state with zero enthalpy. Thus any added quantum turbulence accounts for the entire free energy of the superfluid and there are no other contributions.
In superfluid 3He we can generated and detect quantum turbulence and how it evolves with time, and using bolometric methods, we can measure the energy released as previously-generated turbulence decays, which seems to be unique to these systems.