  Nuclear deformations and density profiles of neutron-rich even-even Zr
isotopes are investigated using the Skyrme-Hartree-Fock-Bogoliubov method.
Large quadrupole and hexadecapole deformations are predicted along with large
enhancement of the total reaction cross sections at the neutron number
$N=60$-74. Strong nuclear deformation starting at $N=60$ is induced by the
occupation of the intruder orbit with the asymptotic quantum number
$[nn_z\Lambda]\Omega$ = [550]1/2 originating from the spherical $0h_{11/2}$
orbit. The deformation region is further enlarged from $N=72$ to 74 owing to
the occupation of the next intruder orbit with [530]1/2 originating from the
spherical $1f_{7/2}$ orbit. This characteristic nuclear deformation is
crucially reflected in the systematic behavior of the nuclear radii and the
density profiles near the nuclear surface.
