\begin{table}%t1 \caption{\label{T:Res}Physical parameters of the different ISM phases.} \par %\centerline { \begin{tabular}{lccccccc} \hline \hline ISM phase & $T$ & $B$ & $n_{\rm H}$ & $f_{\rm ion}$ & $n_{\rm i}$ & $k_{\pa{\rm max}}$ & $E_{\rm k,min}$ \\ & (K) & (${\rm \mu G}$) & (${\rm cm^{-3}}$) & & (${\rm cm^{-3}}$) & (${\rm 10^{-9}~cm^{-1}}$) & (${\rm keV}$)\\ \hline HIM (low $B$) & $10^6$ & 2 & 0.005--0.01 & 1 & 0.005--0.01 & 3.1--4.4 &35--18 \\ HIM (high $B$) & $10^6$ & 20 & 0.005--0.01 & 1 &0.005--0.01 & 3.1--4.4 & 1500--950 \\ WIM & 8000 & 5 & 0.2--0.5 & 0.6--0.9 & 0.12--0.45 & 15--29 & 9.5--2.5 \\ WNM & 6000--10~000 & 5 & 0.2--0.5 & 0.007--0.05 & 0.0014--0.025 & 1.6--6.9 & 540--45 \\ CNM & 50--100 &6 & 20--50 &$4 \times 10^{-4}{-}10^{-3}$ & 0.008--0.05 & 3.9--9.8& 175--32 \\ MM & 10--20 & 8.5--850 & $10^2{-}10^6$ & ${\la}10^{-4}$ & & ${\la}4.4$ & ${\ga}265$ \\ \hline \end{tabular}} \par \medskip Note to the table: The different ISM phases are molecular medium (MM), cold neutral medium (CNM), warm neutral medium (WNM), warm ionized medium (WIM) and hot ionized medium (HIM). $T$ is the temperature, $B$ the magnetic field strength, $n_{\rm H}$ the hydrogen density, $f_{\rm ion} = n_{\rm i} / (n_{\rm i} + n_{\rm n})$ the ionization fraction, $n_{\rm i}$ the ion density, $k_{\pa{\rm max}}$ the maximum parallel wavenumber of Alfv\'en waves (right-hand side of Eq.~(\ref{Eq:thr_kpar_bis})), and $E_{\rm k,min}$ the minimum kinetic energy required for positrons to interact resonantly with Alfv\'en waves (right-hand side of Eq.~(\ref{Eq:thr_KE_bis})). Here, we assume a pure-hydrogen gas, for which $n_{\rm i} = f_{\rm ion} ~ n_{\rm H}$ and $n_{\rm n} = (1 - f_{\rm ion}) ~ n_{\rm H}$. \vspace*{-2mm} \end{table}