def delta_energy(self) -> u.erg:
energy = u.Quantity(
np.where(self._elvlc['E_obs'].value == -1,
self._elvlc['E_th'].value, self._elvlc['E_obs'].value),
self._elvlc['E_obs'].unit)
indices = np.vstack([
vectorize_where(self._elvlc['level'], self.lower_level),
vectorize_where(self._elvlc['level'], self.upper_level)
])
return np.diff(energy[indices], axis=0).flatten() * const.h * const.c
def contribution_function(self, density: u.cm**(-3), **kwargs):
"""
Contribution function :math:`G(n,T)` for all transitions
The contribution function for ion :math:`k` of element :math:`X` for a
particular transition :math:`ij` is given by,
.. math::
G_{ij} = \\frac{n_H}{n_e}\mathrm{Ab}(X)f_{X,k}N_jA_{ij}\Delta E_{ij}\\frac{1}{n_e},
and has units erg :math:`\mathrm{cm}^{3}` :math:`\mathrm{s}^{-1}`. Note that the
contribution function is often defined in differing ways by different authors. The
contribution function is defined as above in [1]_.
The corresponding wavelengths can be retrieved with,
.. code-block:: python
ion.transitions.wavelength[~ion.transitions.is_twophoton]
Parameters
----------
density : `~astropy.units.Quantity`
Electron number density
References
----------
.. [1] Young, P. et al., 2016, J. Phys. B: At. Mol. Opt. Phys., `49, 7 <http://iopscience.iop.org/article/10.1088/0953-4075/49/7/074009/meta>`_
"""
populations = self.level_populations(density, **kwargs)
p2e = proton_electron_ratio(self.temperature, **self._dset_names)
term = np.outer(p2e * self.ioneq,
1. / density.value) * self.abundance / density.unit
# Exclude two-photon transitions
upper_level = self.transitions.upper_level[~self.transitions.
is_twophoton]
# CHIANTI records theoretical transitions with negative wavelengths
wavelength = np.fabs(
self.transitions.wavelength[~self.transitions.is_twophoton])
A = self.transitions.A[~self.transitions.is_twophoton]
energy = ((const.h * const.c) / wavelength).to(u.erg)
i_upper = vectorize_where(self._elvlc['level'], upper_level)
g = term[:, :, np.newaxis] * populations[:, :, i_upper] * (A * energy)
return g
def contribution_function(self, density: u.cm**(-3),
**kwargs) -> u.cm**3 * u.erg / u.s:
r"""
Contribution function :math:`G(n,T)` for all transitions.
The contribution function for ion :math:`k` of element :math:`X` for a
particular transition :math:`ij` is given by,
.. math::
G_{ij} = \frac{n_H}{n_e}\mathrm{Ab}(X)f_{X,k}N_jA_{ij}\Delta E_{ij}\frac{1}{n_e},
Note that the contribution function is often defined in differing ways by different authors.
The contribution function is defined as above in [young]_.
The corresponding wavelengths can be retrieved with,
.. code-block:: python
ion.transitions.wavelength[~ion.transitions.is_twophoton]
Parameters
----------
density : `~astropy.units.Quantity`
Electron number density
References
----------
.. [young] Young, P. et al., 2016, J. Phys. B: At. Mol. Opt. Phys., `49, 7 <http://iopscience.iop.org/article/10.1088/0953-4075/49/7/074009/meta>`_
"""
populations = self.level_populations(density, **kwargs)
term = np.outer(self.ioneq, 1. / density) * self.abundance * 0.83
# Exclude two-photon transitions
upper_level = self.transitions.upper_level[~self.transitions.
is_twophoton]
wavelength = self.transitions.wavelength[~self.transitions.
is_twophoton]
A = self.transitions.A[~self.transitions.is_twophoton]
energy = const.h * const.c / wavelength
i_upper = vectorize_where(self._elvlc['level'], upper_level)
g = term[:, :, np.newaxis] * populations[:, :, i_upper] * (A * energy)
return g