  For homogenous isotropic dielectric nanospheres with incident plane waves,
Cartesian electric and toroidal dipoles can be tunned to cancel each other in
terms of far-field scattering, leading to the effective anopole excitation. At
the same time however, other multipoles such as magnetic dipoles with
comparable scattered power are simultanesouly excited, mixing with the anopole
and leading to a non-negligible total scattering cross section. Here we show
that for homogenous dielectric nanospheres, radial anisotropy can be employed
to significantly suppress the other multipole excitation, which at the same
time does not compromise the property of complete scattering cancallation
between Cartesian electric and toroidal dipoles. This enables an elusive pure
anopole excitation within radially anisotropic dielectric nanospheres, which
may shed new light to many scattering related fundamental researches and
applications.
