\begin{table}%t1
%\centering
\par
\caption{Simulations of Alfv\'{e}n waves in a  
homogeneous medium.
The wave is characterised by the two quantities $\eta$, 
the amplitude of the imposed Alfv\'{e}n wave in terms of the vertical
magnetic field, and $\beta_{\rm }={2 \mu_0 p}/{B_z^2}$ the plasma beta.
For the different Runs we further specify the length of the time step
$\Delta t$ in terms of the period of the wave, $P$,
the length of the computational domain, $L$ in terms of the wave length, 
$\lambda$, and the number of grid points, $N$.}\label{models}
\begin{tabular}{llrlll} 
\hline\hline
Run & $\Delta t/P$ & $N$ & $L/\lambda$ & $\eta$   & $\beta$\\ \hline
1a & 0.003~3 & 3~600 & 78 & 0.007& 0.042\\
1b & 0.003~3 & 3~600 & 78 & 0.07 & 0.042\\
1c & 0.003~3 & 3~600 & 78 & 0.7 & 0.042\\
2a & 0.003~3 & 13~500 & 193  &  0.007 & 0.96\\
2b & 0.003~3 & 13~500 & 193  &  0.07  & 0.96\\
2c & 0.003~3 & 13~500 & 193  &  0.7 & 0.96\\ 
3a & 0.003~3 & 13~500 & 278 &  0.007 & 2\\
3b & 0.003~3 & 13~500 & 278 &  0.07  & 2\\
3c & 0.003~3 & 13~500 & 278 &  0.7  & 2\\
4a & 0.001~7 & 36~000 & 77.2 &  0.007 & 17\\
4b & 0.001~7 & 36~000 & 77.2 &  0.07  & 17\\
4c & 0.001~7 & 36~000 & 77.2 &  0.7   & 17\\ 
\hline
\end{tabular}
\end{table}