\begingroup
\small
\setlength{\tabcolsep}{4pt}
\begin{tabular}{crrr}
\toprule
Grid pair & Full field & $v$ field & $v$ excess field\\
\midrule
256 / 512 & $7.3551\times10^{-3}$ & $2.9502\times10^{-3}$ & $2.0567\times10^{-3}$\\
512 / 1024 & $1.8043\times10^{-3}$ & $2.7704\times10^{-4}$ & $1.4930\times10^{-4}$\\
\bottomrule
\end{tabular}
\endgroup