ion.py 文件源码

def _dere_cross_section(self, energy: u.erg):
        """
        Calculate direct ionization cross-sections according to [1]_.

        References
        ----------
        .. [1] Dere, K. P., 2007, A&A, `466, 771 <http://adsabs.harvard.edu/abs/2007A%26A...466..771D>`_
        """
        # Cross-sections from diparams file
        cross_section_total = np.zeros(energy.shape)
        for ip,bt_c,bt_e,bt_cross_section in zip(self._diparams['ip'], self._diparams['bt_c'], self._diparams['bt_e'],
                                                 self._diparams['bt_cross_section']):
            U = energy/(ip.to(u.erg))
            scaled_energy = 1. - np.log(bt_c)/np.log(U - 1. + bt_c)
            f_interp = interp1d(bt_e.value, bt_cross_section.value, kind='cubic', fill_value='extrapolate')
            scaled_cross_section = f_interp(scaled_energy.value)*bt_cross_section.unit
            # Only nonzero at energies above the ionization potential
            scaled_cross_section *= (U.value > 1.)
            cross_section = scaled_cross_section*(np.log(U) + 1.)/U/(ip**2)
            if not hasattr(cross_section_total, 'unit'):
                cross_section_total = cross_section_total*cross_section.unit
            cross_section_total += cross_section

        return cross_section_total