Technion-Israel Institute of Technology

Department of Physics

Computation Physics Course.
 
  1999 Illia Marderfeld

under supervision of Dr. Erez N. Ribak
 

CORRELATION OF SCINTILLATIONS

Atmospheric turbulence over long horizontal paths perturbs phase and can also case severe intensity scintillation in the pupil of an optical communications receiver.

By using Fourier optics formalism it is possible to get general formulation for the phase and the intensity of the wavefront that passed turbulence layers. From the knowledge phase of different moments of time it is possible  to knowledge of intensity  correlation  between phases and intensity. By finding the correlation maximum in the distribution of correlations we can also find  the changes in the turbulence layer. Specifically the speed at which turbulence is carried in front of the telescope.

This program calculates correlation between scintillations over horizontal path.

The program was written  in MATLAB on the TX and PHLIN1 computers running under the UNIX operating system. Minimal  changes are required for running the program under WINDOWS. The program contains some subroutines, which are to be in the same directory.

To run , type "start_cor" in the command line of  MATLAB. For running program from the description  press 'Close' . For calculation you must have an average of the frames. If it was calculated previously, press the button 'Path to average frame', Click on the file name to serve as the average frame.

Calculation of average of the frames may be obtained by using the checkbox 'Using average', and then by pressing 'Average calculation'.

You must name a file to serve as the average of the frames.

Point to the first frame to be processed, by pressing the button 'Path to first frame'( e.g directory 'pupl/ ')

Click on the first frame. Do not forget to check/change the 'Mask' (the common part of the name of all frames).

You may stop the program by pressing 'Stop' and read again this description by pressing the button 'About'.

You can delete figure by pressing 'Close Fig.'.

I wish to thank AOA Inc for furnishing the data used in this program.

(Click on pictures )


 References:

E.Gershnick, E.N. Ribak Opt. Communication 142(1997) 99-105.

E. Ribak at al. Optics Lett. 21(1996) 435

B. M. Levine at al. Applied Optics 37(1998) 4553.


To the program.


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