Introduction

MegaScreen is a Python 3 package implementing the algorithm described in [Buscher2016]. This algorithm aims to simulate with high accuracy the wavefront perturbations arising from optical propagation through Kolmogorov turbulence. The abstract of the paper reads:

We describe an algorithm for simulating atmospheric wavefront perturbations over ranges of spatial and temporal scales spanning more than 4 orders of magnitude. An open-source implementation of the algorithm written in Python can simulate the evolution of the perturbations more than an order-of-magnitude faster than real time. Testing of the implementation using metrics appropriate to adaptive optics systems and long-baseline interferometers show accuracies at the few percent level or better.

The algorithm superposes two phase screens containing high-frequency (“tweeter”) and low-frequency (“woofer”) perturbations respectively. An example result can be seen in the figure below, where the x- and y-direction structure functions of the individual screens are compared to the theoretical structure function, and their sum is shown on the right. The sum clearly matches theoretical predictions to a high degree of accuracy.

To see a short movie of the phase screens generated by this module, see https://nbviewer.jupyter.org/github/dbuscher/megascreen/blob/master/tests/demos/phase_screen_movie.ipynb

The following sections describe how to install and use the MegaScreen package, starting from the simplest usage and moving on to more detailed explanations of how to choose parameters of the main MegaScreen() function call to suit different applications.

Buscher2016

Buscher, D.F. “Simulating Large Atmospheric Phase Screens Using a Woofer-Tweeter Algorithm.” Optics Express 24, no. 20 (October 3, 2016): 23566–71. https://doi.org/10.1364/OE.24.023566.