  Vortex-flows exist across a broad range of spatial and temporal scales in the
solar atmosphere. Small-scale vortices have been proposed to play an important
role in energy transport in the solar atmosphere. However, their physical
properties remain poorly understood due to the limited spatial resolution of
the observations. We aim to explore and analyze the physical properties of
small-scale vortices inside magnetic flux tubes using numerical simulations,
and to investigate whether they contribute to heating the chromosphere in a
plage region. Using the three-dimensional (3D) radiative magnetohydrodynamic
(MHD) simulation code 'MURaM', we perform numerical simulations of a unipolar
solar plage region. To detect and isolate vortices, we use the Swirling
Strength criterion and select the locations where the fluid is rotating with an
angular velocity greater than a certain threshold. We concentrate on
small-scale as they are the strongest and carry most of the energy. We explore
the spatial profiles of physical quantities viz. density, horizontal velocity,
etc. inside these vortices. Moreover, to apprehend their general
characteristics, a statistical investigation is performed. Magnetic flux tubes
have a complex filamentary substructure harbouring an abundance of small-scale
vortices. At the interfaces between vortices strong current sheets are formed
that may dissipate and heat the solar chromosphere. Statistically, vortices
have higher densities and higher temperatures than the average values at the
same geometrical height in the chromosphere. We conclude that small-scale
vortices are ubiquitous in solar plage regions, and they are denser and hotter
structures that contribute to chromospheric heating, possibly by dissipation of
the current sheets formed at their interfaces.
