Hopf bifurcation to convection near the codimension-two point in a 3He-4He mixture.
From measurements of the convective heat transport in a normal 3He-4He mixture over the range −0.018≲ψ≲0.015 of the separation ratio ψ, we found a time-periodic state for ψ<ψCT=−0.0044. The dimensionless onset frequency at ψCT was 1.42, much larger than the value predicted by linear-stability analysis for a spatially uniform, laterally infinite system. For ψCT>ψ>ψc≈−0.010 the bifurcation to oscillations was forward while for ψ≲ψc it was backward. The results suggests that ψc is an additional codimension-two point, rather than a Hopf tricritical point.
Sullivan, Timothy and Ahlers, Guenter, "Hopf bifurcation to convection near the codimension-two point in a 3He-4He mixture." (1988). Physical Review Letters 61(1): 78-81. Faculty Publications. Paper 307.
Physical Review Letters