  Nanoflare heating through small-scale magnetic reconnection events is one of
the prime candidates to explain heating of the solar corona. However, direct
signatures of nanoflares are difficult to determine, and unambiguous
observational evidence is still lacking. Numerical models that include
accelerated electrons and can reproduce flaring conditions are essential in
understanding how low-energetic events act as a heating mechanism of the
corona, and how such events are able to produce signatures in the spectral
lines that can be detected through observations. We investigate the effects of
accelerated electrons in synthetic spectra from a 3D radiative
magnetohydrodynamics simulation to better understand small-scale heating events
and their impact on the solar atmosphere. We synthesised the chromospheric Ca
II and Mg II lines and the transition region Si IV resonance lines from a quiet
Sun numerical simulation that includes accelerated electrons. We calculated the
contribution function to the intensity to better understand how the lines are
formed, and what factors are contributing to the detailed shape of the spectral
profiles. The synthetic spectra are highly affected by variations in
temperature and vertical velocity. Beam heating exceeds conductive heating at
the heights where the spectral lines form, indicating that the electrons should
contribute to the heating of the lower atmosphere and hence affect the line
profiles. However, we find that it is difficult to determine specific
signatures from the non-thermal electrons due to the complexity of the
atmospheric response to the heating in combination with the relatively low
energy output (~1e21 erg/s). Even so, our results contribute to understanding
small-scale heating events in the solar atmosphere, and give further guidance
to future observations.
