Back to the subseismic approximation for core undertones

摘要: The problem of the long-period gravity modes Earth outer fluid core is investigated using either subseismic or anelastic approximation These two approximations aim at filtering out uninteresting short-period seismic acoustic oscillations while taking into account density variations across However, they differ on form equation mass conservation since perturbations do not contribute to balance in case Here we show that these lead almost same results because weakness stratification due convective mixing should be however preferred it simpler, mathematically self-consistent and only one which can applied problems with a stronger such as ones encountered radiative zones stars