Fast Alpha Pressure Contribution
The pressure contribution from the fast alpha particles can be controlled using switch ifalphap.
There are two options 11 and 22:
\begin{aligned}
\frac{\beta_{\alpha}}{\beta_{th}} & = 0.29 \, \left( \langle T_{10} \rangle -
0.37 \right) \, \left( \frac{n_{DT}}{n_e} \right)^2
\hspace{20mm} \mbox{if alphap = 0} \\
\frac{\beta_{\alpha}}{\beta_{th}} & = 0.26 \, \left( \langle T_{10} \rangle -
0.65 \right)^{0.5} \, \left( \frac{n_{DT}}{n_e} \right)^2
\hspace{16mm} \mbox{if alphap = 1 (default)}
\end{aligned}
The latter model is a better estimate at higher temperatures.