We generate quantum turbulence in spherically symmetric thermal counterflow of superfluid ${}^4\mathrm{He}$ driven by a central heater and probe it by second sound attenuation. We show that normal fluid turbulence forms above a certain critical threshold and, in the absence of shear flow, draws energy from a preexisting random tangle of quantized vortices corresponding to Vinen-type turbulence. This experiment can serve as a model flow for cosmological phenomena relating cosmic strings to quantized vortices, for processes occurring in neutron stars, or cosmological structure formation within superfluid models of dark matter.

• Received 20 February 2023
• Accepted 21 December 2023

DOI:https://doi.org/10.1103/PhysRevFluids.9.L022601