spectral_density_lite

plasmapy.diagnostics.thomson.spectral_density_lite(
wavelengths,
probe_wavelength: float,
n: float,
T_e: ndarray,
T_i: ndarray,
efract: ndarray,
ifract: ndarray,
ion_z: ndarray,
ion_mass: ndarray,
electron_vel: ndarray,
ion_vel: ndarray,
probe_vec: ndarray,
scatter_vec: ndarray,
instr_func_arr: ndarray | None = None,
notch: ndarray | None = None,
) → tuple[floating | ndarray, ndarray][source]

The lite-function version of spectral_density. Performs the same thermal speed calculations as spectral_density, but is intended for computational use and thus has data conditioning safeguards removed.

Parameters:

  • wavelengths ((NΞ»,) ndarray) – The wavelengths in meters over which the spectral density function will be calculated.

  • probe_wavelength (real number) – Wavelength of the probe laser in meters.

  • n (ndarray) – Total combined number density of all electron populations in m-3.

  • T_e ((Ne,) ndarray) – Temperature of each electron population in kelvin, where Ne is the number of electron populations.

  • T_i ((Ni,) ndarray) – Temperature of each ion population in kelvin, where Ni is the number of ion populations.

  • efract ((Ne,) ndarray) – An ndarray where each element represents the fraction (or ratio) of the electron population number density to the total electron number density. Must sum to 1.0. Default is a single electron population.

  • ifract ((Ni,) ndarray) – An ndarray object where each element represents the fraction (or ratio) of the ion population number density to the total ion number density. Must sum to 1.0. Default is a single ion species.

  • ion_z ((Ni,) ndarray) – An ndarray of the charge number \(Z\) of each ion species.

  • ion_mass ((Ni,) ndarray) – An ndarray of the mass number of each ion species in kg.

  • electron_vel ((Ne, 3) ndarray) – Velocity of each electron population in the rest frame (in m/s). If set, overrides electron_vdir and electron_speed. Defaults to a stationary plasma [0, 0, 0] m/s.

  • ion_vel ((Ni, 3) ndarray) – Velocity vectors for each electron population in the rest frame (in m/s). If set, overrides ion_vdir and ion_speed. Defaults to zero drift for all specified ion species.

  • probe_vec ((3,) float ndarray) – Unit vector in the direction of the probe laser. Defaults to [1, 0, 0].

  • scatter_vec ((3,) float ndarray) – Unit vector pointing from the scattering volume to the detector. Defaults to [0, 1, 0] which, along with the default probe_vec, corresponds to a 90 degree scattering angle geometry.

  • instr_func_arr (ndarray, shape (Nwavelengths,) optional) –

    The instrument function evaluated at a linearly spaced range of wavelengths ranging from \(-W\) to \(W\), where

    \[W = 0.5*(\max{Ξ»} - \min{Ξ»})\]

    Here \(Ξ»\) is the wavelengths array. This array will be convolved with the spectral density function before it is returned.

  • notch ((2,) or (N, 2) ndarray, keyword-only, optional) – A pair of wavelengths in meters which are the endpoints of a notch over which the output Skw is set to 0. Can also be input as a 2D array which contains many such pairs if multiple notches are needed. Defaults to no notch.

Returns:

  • alpha (float) – Mean scattering parameter, where alpha > 1 corresponds to collective scattering and alpha < 1 indicates non-collective scattering. The scattering parameter is calculated based on the total plasma density \(n\).

  • Skw (ndarray) – Computed spectral density function over the input wavelengths array with units of s/rad.