  The impact of impurities on the generation of zonal flow (ZF) driven by
collisonless trapped electron mode (CTEM) turbulence in deuterium (D)-tritium
(T) plasmas is investigated. The expression for ZF growth rate with impurities
is derived by balancing the ZF potential shielded by polarization effects and
the ZF modulated radial turbulent current. Then, it is shown that the maximum
normalized ZF growth rate is reduced by the presence of the fully ionized
non-trace light impurities with relatively flat density profile, and slightly
reduced by highly ionized trace tungsten (W). While, the maximum normalized ZF
growth rate can be also enhanced by fully ionized non-trace light impurities
with relatively steep density profile. In particular, the effects of high
temperature helium from D-T reaction on ZF depend on the temperature ratio
between electron and high temperature helium. The possible relevance of our
findings to recent experimental results and future burning plasmas is also
discussed.
