  A meron is a controversial topological excitation because it carries just one
half of the topological charge unit. It is believed that it is tightly binded
to another meron and cannot be observed by isolating it. We present a counter
example, investigating the 2-dimensional nonlinear sigma model together with
the Dzyaloshinskii-Moriya interaction, where topological excitations are
merons, bimerons and skyrmions. They behave as if they were free particles
since they are electrically neutral. A prominent feature is that the
topological charge density is strictly confined within compact domains. We
propose an analytic approach for these compact excitations, and construct a
phase diagram. It is comprised of the helix, meron, skyrmion-crystal,
skyrmion-gas and ferromagnet phases. It explains quite well the experimental
data recently performed in chiral magnets such as MnSi and FeCoSi thin films,
as verifies that merons are surely basic topological excitations in the system.
