  The linear stability of chains of magnetic vortices in a plasma is
investigated analytically in two dimensions by means of a reduced fluid model
assuming a strong guide field and accounting for equilibrium electron
temperature anisotropy. The chain of magnetic vortices is modelled by means of
the classical "cat's eyes" solutions and the linear stability is studied by
analysing the second variation of a conserved functional, according to the
Energy-Casimir method. The stability analysis is carried out on the domain
bounded by the separatrices of the vortices. Two cases are considered,
corresponding to a ratio between perpendicular equilibrium ion and electron
temperature much greater or much less than unity, respectively. In the former
case, equilibrium flows depend on an arbitrary function. Stability is attained
if the equilibrium electron temperature anisotropy is bounded from above and
from below, with the lower bound corresponding to the condition preventing the
firehose instability. A further condition sets an upper limit to the amplitude
of the vortices, for a given choice of the equilibrium flow. For cold ions, two
sub-cases have to be considered. In the first one, equilibria correspond to
those for which the velocity field is proportional to the local Alfv\'en
velocity. Stability conditions imply: an upper limit on the amplitude of the
flow, which automatically implies firehose stability, an upper bound on the
electron temperature anisotropy and again an upper bound on the size of the
vortices. The second sub-case refers to equilibrium electrostatic potentials
which are not constant on magnetic flux surfaces and the resulting stability
conditions correspond to those of the first sub-case in the absence of flow.
