  This work presents the results of a multi mode ITER study on Toroidal Alfven
Eigenmodes, using the nonlinear hybrid HAGIS-LIGKA model. It is found that main
conclusions from earlier studies of ASDEX Upgrade discharges can be transferred
to the ITER scenario: global, nonlinear effects are crucial for the evolution
of the multi mode scenario. This work focuses on the ITER 15 MA baseline
scenario with with a safety factor at the magnetic axis of $q_0 =$ 0.986. The
least damped eigenmodes of the system are identified with the gyrokinetic,
non-perturbative LIGKA solver, concerning mode structure, frequency and
damping. Taking into account all weakly damped modes that can be identified
linearly, nonlinear simulations with HAGIS reveal strong multi mode behavior:
while in some parameter range, quasi-linear estimates turn out to be reasonable
approximations for the nonlinearly relaxed energetic particle profile, under
certain conditions low-n TAE branches can be excited. As a consequence, not
only grow amplitudes of all modes to (up to orders of magnitude) higher values
compared to the single mode cases but also, strong redistribution is triggered
in the outer radial area between $\rho_\mathrm{pol} =$ 0.6 and 0.85, far above
quasi-linear estimates.
