  We present analytical results concerning the magneto-roton instability in
higher Landau levels evaluated in the single mode approximation. The roton gap
appears at a finite wave vector, which is approximately independent of the LL
index n, in agreement with numerical calculations in the composite-fermion
picture. However, a large maximum in the static susceptibility indicates a
charge density modulation with wave vectors $q_0(n)\sim 1/\sqrt{2n+1}$, as
expected from Hartree-Fock predictions. We thus obtain a unified description of
the leading charge instabilities in all LLs.
