\begin{table}%t2
      \caption{\label{tab:exponents}The table shows the exponent $\alpha$ of the fitted power laws~$\tau^\alpha$
             for the quantities~$l_{\rm c}$ (cocoon length), $r_{\rm e}$ (extended cocoon radius) and~$r_{\rm i}$ (internal cocoon radius). The left column refers to the initial phase
             of the evolution of the cocoon ($l_{\rm c} <1.0$) while the second one to the   advanced one ($l_{\rm c} >1.5$)}
%\centering
\par
\begin{tabular}{ccc}
  \hline \hline\noalign{\smallskip}
  $\nu$ = 0.1 & $l_{\rm c}$~ $<$ 1.0 & $l_{\rm c}$~ $>$ 1.5 \\ \noalign{\smallskip}\hline\noalign{\smallskip}
  $l_{\rm c}$ & 0.85 & 0.85 \\
  $r_{\rm e}$ & 0.54 & 0.67 \\
  $r_{\rm i}$ & 0.43 & 0.56 \\
\noalign{\smallskip}
  \hline \hline\noalign{\smallskip}
  $\nu$ = 0.01 & $l_{\rm c}$~ $<$ 1.0 & $l_{\rm c}$~ $>$ 1.5 \\ \noalign{\smallskip}\hline\noalign{\smallskip}
  $l_{\rm c}$ & 0.75 & 0.95 \\
  $r_{\rm e}$ & 0.56 & 0.71 \\
  $r_{\rm i}$ & 0.45 & 0.53 \\ \noalign{\smallskip}
  \hline \hline\noalign{\smallskip}
  $\nu$ = 0.001 & $l_{\rm c}$~ $<$ 1.0 & $l_{\rm c}$~ $>$ 1.5 \\  \noalign{\smallskip}\hline\noalign{\smallskip}
  $l_{\rm c}$ & 0.77 & 0.89 \\
  $r_{\rm e}$ & 0.69 & 0.81 \\
  $r_{\rm i}$ & 0.46 & 0.07 \\ \hline
\end{tabular} 
\end{table}