  We study the behavior of the confining flux tube in $N_f=2+1$ QCD at the
physical point, discretized with the stout smearing improved staggered quark
action and the tree level Symanzik gauge action. We discuss how it depends on a
uniform external magnetic field, showing how it displays anisotropies with
respect to the magnetic field direction. Moreover, we compare the observed
anisotropy pattern with that of the static quark-antiquark potential we
obtained in our previous works.
