  The capability of the global, electromagnetic gyrokinetic GENE code
interfaced with the transport Tango solver is exploited to address the impact
of fusion alpha particles (in their dual role of fast particles and heating
source) on plasma profiles and performance at JET in the discharges with the
highest quasi-stationary peak fusion power during the DTE2 experimental
campaigns. Employing radially global nonlinear electromagnetic GENE-Tango
simulations, we compare results with/without alpha particles and alpha heating.
Our findings reveal that alpha particles have a negligible impact on turbulent
transport, with GENE-Tango converging to similar plasma profiles regardless of
their inclusion as a kinetic species in GENE. On the other hand, alpha heating
is found to contribute to the peaking of the electron temperature profiles,
leading to a 1keV drop on the on-axis electron temperature when alpha heating
is neglected in Tango. The minimal impact of alpha particles on turbulent
transport in this JET discharge - despite this being the shot with the highest
fusion output - is attributed to the low content of fusion alpha in this
discharge. To assess the potential impact of alpha particles on turbulent
transport in regimes with higher alpha particle density, as expected in ITER
and fusion reactors, we artificially increased the alpha particle concentration
to levels expected for ITER. By performing global nonlinear GENE standalone
simulations, we found that increasing the alpha particle density beyond five
times the nominal value lead to significant overall turbulence destabilization.
