  Non-adiabatic electron response leads to significant changes in Ion
Temperature Gradient (ITG) eigenmodes, leading in particular to fine-structures
that are significantly extended along the magnetic field lines at corresponding
Mode Rational Surfaces (MRSs). These eigenmodes can nonlinearly interact with
themselves to drive zonal flows via the so-called self-interaction mechanism.
In this paper, the effect of collisions on these processes are studied. In
presence of non-adiabatic electrons, the linear growth rate of ITG eigenmodes
decreases with increasing collisionality. Detailed velocity space analysis of
the distribution function shows that this results from collisions leading to a
more adiabatic-like response of electrons away from MRSs. In linear
simulations, collisions are furthermore found to broaden the radial width of
the fine-structures, which translates to narrower tails of the eigenmode in
extended ballooning space. The characteristic parallel scale length associated
to these tails is shown to scale with the mean free path of electrons. In
nonlinear turbulence simulations accounting for physically relevant values of
collisionality, the fine structures located at MRSs, together with the
associated drive of zonal flows via self-interaction, are shown to persist and
play a significant role.
