  Context. Coronal heating is currently thought to proceed via the mechanism of
nanoflares, small-scale and possibly recurring heating events that release
magnetic energy. Aims. We investigate the effects of a periodic high-energy
electron beam on the synthetic spectra of coronal Fe ions. Methods. Initially,
the coronal plasma is assumed to be Maxwellian with a temperature of 1 MK. The
high-energy beam, described by a kappa-distribution, is then switched on every
period $P$ for the duration of P/2. The periods are on the order of several
tens of seconds, similar to exposure times or cadences of space-borne
spectrometers. Ionization, recombination, and excitation rates for the
respective distributions are used to calculate the resulting non-equilibrium
ionization state of Fe and the instantaneous and period-averaged synthetic
spectra. Results. Under the presence of the periodic electron beam, the plasma
is out of ionization equilibrium at all times. The resulting spectra averaged
over one period are almost always multithermal if interpreted in terms of
ionization equilibrium for either a Maxwellian or a kappa-distribution.
Exceptions occur, however; the EM-loci curves appear to have a nearly
isothermal crossing-point for some values of kappa_s. The instantaneous spectra
show fast changes in intensities of some lines, especially those formed outside
of the peak of the respective EM(T) distributions if the ionization equilibrium
is assumed.
