  We revisit the problem of semiclassical spectral asymptotics for a pure
magnetic Schr\"odinger operator on a two-dimensional Riemannian manifold. We
suppose that the minimal value $b_0$ of the intensity of the magnetic field is
strictly positive, and the corresponding minimum is unique and non-degenerate.
The purpose is to get the control on the spectrum in an interval $(hb_0, h(b_0
+\gamma_0)]$ for some $\gamma_0>0$ independent of the semiclassical parameter
$h$. The previous papers by Helffer-Mohamed and by Helffer-Kordyukov were only
treating the ground-state energy or a finite (independent of $h$) number of
eigenvalues. Note also that N. Raymond and S. Vu Ngoc have recently developed a
different approach of the same problem.
