  Using one-dimensional numerical simulations, we study the elementary process
of Alfv\'{e}n wave reflection in a uniform medium, including nonlinear effects.
In the linear regime, Alfv\'{e}n wave reflection is triggered only by the
inhomogeneity of the medium, whereas in the nonlinear regime, it can occur via
nonlinear wave-wave interactions. Such nonlinear reflection (backscattering) is
typified by decay instability. In most studies of decay instabilities, the
initial condition has been a circularly polarized Alfv\'{e}n wave. In this
study we consider a linearly polarized Alfv\'en wave, which drives density
fluctuations by its magnetic pressure force. For generality, we also assume a
broadband wave with a red-noise spectrum. In the data analysis, we decompose
the fluctuations into characteristic variables using local eigenvectors, thus
revealing the behaviors of the individual modes. Different from
circular-polarization case, we find that the wave steepening produces a new
energy channel from the parent Alfv\'en wave to the backscattered one. Such
nonlinear reflection explains the observed increasing energy ratio of the
sunward to the anti-sunward Alfv\'{e}nic fluctuations in the solar wind with
distance against the dynamical alignment effect.

Solar and Stellar Astrophysics