Stability of the solar latitudinal differential rotation inferred from helioseismic data

We revisit the hydrodynamical stability problem posed by the observed solar latitudinal differential rotation. Specifically, we carry out stability an alyses on a spherical shell for solar-like two-dimensional inviscid shear f low profiles of the form upsilon = s(0) - s(2) mu(2) - s(4) mu(4), where mu is the sine of latitude. We find that stability is remarkably sensitive to the magnitude of the mu(4) term. This allows us to reconcile apparently co nflicting results found in the published literature. We then use latitudina l differential rotation profiles extracted from various helioseismic invers ions of the solar internal rotation and investigate their stability as a fu nction of depth from the base of the tachocline to the top of the convectiv e envelope. In all cases considered, we find that the latitudinal different ial rotation in the tachocline is stable while that in the bulk of the conv ective envelope is unstable. Under the assumption that the instability is n ot impeded by finite Reynolds number or three-dimensional effects not accou nted for in our analysis, we speculate on possible observable consequences of the occurrence of the instability in the top half of the convective enve lope.