\noindentSolutions
(\ref{nrokRe}) have the following properties.
The function \(n^{\prime(x)}(\mathbf{r},\tau_{x})\), as well as
\(n^{(x)}(\mathbf{r},t)\), is even with respect to \(y\). Since
\({\frac{\omega_{x}^{\prime\prime}}{\omega_{x}^{\prime}}\ll 1}\), the
amplitude of this function changes slightly within several periods.
At \({V_{0}=0}\), \(n^{\prime(x)}(\mathbf{r},\tau_{x})\) is an
odd function of the coordinate \(x\). In general, \(n^{\prime(x)}(\mathbf{r},\tau_{x})\) describes the behavior of charge waves in the two-dimensional
space and in time.