  Instabilities in oscillating loops are believed to be essential for
dissipating the wave energy and heating the solar coronal plasma. Our aim is to
study the development of the Kelvin-Helmholtz (KH) instability in an
oscillating loop that is driven by random footpoint motions. Using the PLUTO
code, we performed 3D simulations of a straight gravitationally stratified flux
tube. The loop footpoints are embedded in chromospheric plasma, in the presence
of thermal conduction and an artificially broadened transition region. Using
drivers with a power-law spectrum, one with a red noise spectrum and one with
the low-frequency part subtracted, we excited standing oscillations and the KH
instability in our loops, after one-and-a-half periods of the oscillation. We
see that our broadband drivers lead to fully deformed, turbulent loop
cross-sections over the entire coronal part of the loop due to the spatially
extended KH instability. The low RMS velocity of our driver without the
low-frequency components supports the working hypothesis that the KH
instability can easily manifest in oscillating coronal loops. We report for the
first time in driven transverse oscillations of loops the apparent propagation
of density perturbations due to the onset of the KH instability, from the apex
towards the footpoints. Both drivers input sufficient energy to drive enthalpy
and mass flux fluctuations along the loop, while also causing heating near the
driven footpoint of the oscillating loop, which becomes more prominent when a
low-frequency component is included in the velocity driver. Finally, our
power-law driver with the low-frequency component provides a RMS input Poynting
flux of the same order as the radiative losses of the quiet-Sun corona, giving
us promising prospects for the contribution of decayless oscillations in
coronal heating.
