  We consider a charged scalar field under the effect of an external uniform
magnetic field in the near-horizon geometry of the Banados-Teitelboim-Zanelli
black hole with torsion and obtain quasi-stationary states of the system under
consideration through obtaining analytical solution of the corresponding
Klein-Gordon equation. We obtain the solution function of the equation and
accordingly we arrive at a complex spectra. We observe that the real
oscillation frequency of the modes and their decay time depends on the strength
of the external magnetic field besides the parameters of the geometric
background. We see that the amplitude of the real oscillation modes decreases
and the decay time of the modes becomes longer as the strength of the external
magnetic field increases. The results also indicate that the geometric
background is stable under such a perturbation field.
