1 Description, capabilities

The software is written to produce realistic atmospheric turbulence wavefront series. It can be used by itself to simply compute wavefronts or as part of an Adaptive Optics system simulation
Main features:

Atmosphere model : Chromaticity

The optical pathlength difference (wavefront) and intensity distribution (scintillation) at the telescope pupil are chromatic: To take into account these effects, the vertical distribution of refractive index in the atmosphere needs to be known as a function of wavelength.

Density

The vertical distribution of atmosphere density is obtained from the US standard atmosphere model ( ASCII table). The refractivity (= 1 - refraction index) is assumed to be proportional to this density.

Wavelength

The refractive index as a function of wavelength lambda (unit = um) is:
n(lambda) = 1 + 5792105E-8/(238.0185-pow(lambda,-2)) + 167917E-8/(57.362-pow(lambda,-2))
Standard Air: dry air at 15 °C, 101 325 Pa and with 450 ppm CO2 content
Ref: Philip E. Ciddor. Refractive index of air: new equations for the visible and near infrared, Appl. Optics 35, 1566-1573 (1996)
Reference: Refractive index of air: new equations for the visible and near infrared.

Turbulence profile

The turbulence profile is specified in an ASCII file named "turbul.prof". An example turbulence profile, used for Mauna Kea, is shown below (Courtesy of Mark Chun, IfA).
# altitude(m)   relativeCN2     speed(m/s)      direction(rad)

4215		5.32		6.5		1.47
4230		1.47		6.55		1.57
4349		1.08		6.6		1.67
5007		2.11		6.7		1.77
12200		1.83		22.0		4.7
16200		1.48		9.5		4.8
23701		0.697		5.6		4.9
References:

2 Download and install

The source code is hosted on github: https://github.com/oguyon/AtmosphericTurbulence .
The program is written in C and installation follows the standard GNU build process (configure, make, make install). The github repository holds a gzipped tarball for installation of the latest version.

The following libraries are required:

3 Usage

Create the configuration and turbulence profile ASCII files

The program requires two files to run:

Run the turbulence sequence generator

Type:
./bin/atmturb
mktwfs