Mie scattering of a plane wave by a sphere

Project description

by Scott Prahl

miepython is a pure Python module to calculate light scattering for non-absorbing, partially-absorbing, or perfectly-conducting spheres. Mie theory is used, following the procedure described by Wiscombe. This code has been validated against his results.

This code provides functions for calculating the extinction efficiency, scattering efficiency, backscattering, and scattering asymmetry. Moreover, a set of angles can be given to calculate the scattering for a sphere at each of those angles.

Pay Attention!

When comparing different Mie scattering codes, make sure that you’re aware of the conventions used by each code. miepython makes the following assumptions

1. the imaginary part of the complex index of refraction for absorbing spheres is negative.

2. the scattering phase function is normalized so it equals the single scattering albedo when integrated over 4π steradians. As of version 2.3, this can be changed.

Using miepython

1. You can install locally using pip:

pip install --user miepython
2. or run this code in the cloud using Google Collaboratory by selecting the Jupyter notebook that interests you.

An example

The following code:

import miepython

m = 1.5-1j
x = 1
qext, qsca, qback, g = miepython.mie(m,x)

print("The extinction efficiency  is %.3f" % qext)
print("The scattering efficiency  is %.3f" % qsca)
print("The backscatter efficiency is %.3f" % qback)
print("The scattering anisotropy  is %.3f" % g)

should produce:

The extinction efficiency  is 2.336
The scattering efficiency  is 0.663
The backscatter efficiency is 0.573
The scattering anisotropy  is 0.192

Here are a few short scripts in the github repository.

Detailed documentation is available at <https://miepython.readthedocs.io>

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