Convection in Dilute Solutions ofHe3in SuperfluidHe4

Thermal convection in dilute solutions of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ in superfluid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ has been studied in a novel cell of unity aspect ratio which permits inhomogeneity in the heat flux to be measured. At least three different convecting states have been observed, including a time-dependent state with diminished thermal conductance which can exist very close to the onset of convection.