IonizationStateCollection

class plasmapy.particles.IonizationStateCollection(inputs: Union[Dict[str, numpy.ndarray], List, Tuple], *, T_e: Unit("K") = <Quantity nan K>, abundances: Optional[Dict[str, numbers.Real]] = None, log_abundances: Optional[Dict[str, numbers.Real]] = None, n0: Unit("1 / m3") = <Quantity nan 1 / m3>, tol: numbers.Real = 1e-15, kappa: numbers.Real = inf)

Bases: object

Describe the ionization state distributions of multiple elements or isotopes.

Parameters
  • inputs (list, tuple, or dict) – A list or tuple of elements or isotopes (if T_e is provided); a list of IonizationState instances; a dict with elements or isotopes as keys and a ndarray of ionic fractions as the values; or a dict with elements or isotopes as keys and Quantity instances with units of number density.

  • abundances (dict, optional, keyword-only) – A dict with ParticleLike objects used as the keys and the corresponding relative abundance as the values. The values must be positive real numbers.

  • log_abundances (dict, optional, keyword-only) – A dict with ParticleLike objects used as the keys and the corresponding base 10 logarithms of their relative abundances as the values. The values must be real numbers.

  • n0 (Quantity, optional, keyword-only) – The number density normalization factor corresponding to the abundances. The number density of each element is the product of its abundance and n0.

  • T_e (Quantity, optional, keyword-only) – The electron temperature in units of temperature or thermal energy per particle.

  • kappa (float, optional, keyword-only) – The value of kappa for a kappa distribution function.

  • tol (float or integer, optional, keyword-only) – The absolute tolerance used by isclose when testing normalizations and making comparisons. Defaults to 1e-15.

Raises

ParticleError – If IonizationStateCollection cannot be instantiated.

Examples

>>> from astropy import units as u
>>> from plasmapy.particles import IonizationStateCollection
>>> states = IonizationStateCollection(
...     {'H': [0.5, 0.5], 'He': [0.95, 0.05, 0]},
...     T_e = 1.2e4 * u.K,
...     n0 = 1e15 * u.m ** -3,
...     abundances = {'H': 1, 'He': 0.08},
... )
>>> states.ionic_fractions
{'H': array([0.5, 0.5]), 'He': array([0.95, 0.05, 0.  ])}

The number densities are given by the ionic fractions multiplied by the abundance and the number density scaling factor n0.

>>> states.number_densities['H']
<Quantity [5.e+14, 5.e+14] 1 / m3>
>>> states['He'] = [0.4, 0.59, 0.01]

To change the ionic fractions for a single element, use item assignment.

>>> states = IonizationStateCollection(['H', 'He'])
>>> states['H'] = [0.1, 0.9]

Item assignment will also work if you supply number densities.

>>> states['He'] = [0.4, 0.6, 0.0] * u.m ** -3
>>> states.ionic_fractions['He']
array([0.4, 0.6, 0. ])
>>> states.number_densities['He']
<Quantity [0.4, 0.6, 0. ] 1 / m3>

Notes

No more than one of abundances and log_abundances may be specified.

If the value provided during item assignment is a Quantity with units of number density that retains the total element density, then the ionic fractions will be set proportionately.

When making comparisons between IonizationStateCollection instances, nan values are treated as equal. Equality tests are performed to within a tolerance of tol.

Attributes Summary

T_e

Return the electron temperature.

abundances

Return the elemental abundances.

base_particles

Return a list of the elements and isotopes whose ionization states are being kept track of.

ionic_fractions

Return a dict containing the ionic fractions for each element and isotope.

kappa

Return the kappa parameter for a kappa distribution function for electrons.

log_abundances

Return a dict with atomic or isotope symbols as keys and the base 10 logarithms of the relative abundances as the corresponding values.

n0

Return the number density scaling factor.

n_e

Return the electron number density under the assumption of quasineutrality.

number_densities

Return a dict containing the number densities for element or isotope.

tol

Return the absolute tolerance for comparisons.

Methods Summary

normalize()

Normalize the ionic fractions so that the sum for each element equals one.

summarize([minimum_ionic_fraction])

Print quicklook information for an IonizationStateCollection instance.

Attributes Documentation

T_e

Return the electron temperature.

abundances

Return the elemental abundances.

base_particles

Return a list of the elements and isotopes whose ionization states are being kept track of.

ionic_fractions

Return a dict containing the ionic fractions for each element and isotope.

The keys of this dict are the symbols for each element or isotope. The values will be ndarray objects containing the ionic fractions for each ionization level corresponding to each element or isotope.

kappa

Return the kappa parameter for a kappa distribution function for electrons.

The value of kappa must be greater than 1.5 in order to have a valid distribution function. If kappa equals inf, then the distribution function reduces to a Maxwellian.

log_abundances

Return a dict with atomic or isotope symbols as keys and the base 10 logarithms of the relative abundances as the corresponding values.

n0

Return the number density scaling factor.

n_e

Return the electron number density under the assumption of quasineutrality.

number_densities

Return a dict containing the number densities for element or isotope.

tol

Return the absolute tolerance for comparisons.

Methods Documentation

normalize()None

Normalize the ionic fractions so that the sum for each element equals one.

summarize(minimum_ionic_fraction: numbers.Real = 0.01)None

Print quicklook information for an IonizationStateCollection instance.

Parameters

minimum_ionic_fraction (Real) – If the ionic fraction for a particular ionization state is below this level, then information for it will not be printed. Defaults to 0.01.

Examples

>>> states = IonizationStateCollection(
...     {'H': [0.1, 0.9], 'He': [0.95, 0.05, 0.0]},
...     T_e = 12000 * u.K,
...     n0 = 3e9 * u.cm ** -3,
...     abundances = {'H': 1.0, 'He': 0.1},
...     kappa = 3.4,
... )
>>> states.summarize()
IonizationStateCollection instance for: H, He
----------------------------------------------------------------
H  0+: 0.100    n_i = 3.00e+14 m**-3
H  1+: 0.900    n_i = 2.70e+15 m**-3
----------------------------------------------------------------
He  0+: 0.950    n_i = 2.85e+14 m**-3
He  1+: 0.050    n_i = 1.50e+13 m**-3
----------------------------------------------------------------
n_e = 2.71e+15 m**-3
T_e = 1.20e+04 K
kappa = 3.40
----------------------------------------------------------------