BvU said:Hello eahaidar,
Don't you think that is a bit terse ? Some explanation of the variables might be in order. Complex variables ? Probably: in particular: g -- if g is real nothing happens.
Below is the homework template; you case may not be a homework exercise, but the systematic approach might be useful anyway !
1. The problem statement, all variables and given/known data
2. Homework Equations
3. The Attempt at a Solution
I still see an ##|A_0|^2## sitting there. is it constant and equal to 1 ? But even d(I0) /dz = (d( ISBS)/dz)/A02 + d(I STOKES)/dz is enough to reduce this to a two differential equations problem -- doesn't change the suggestion.eahaidar said:What I meant from 1=2 +3 is that notice that d(I0) /dz = d( ISBS)/dz + d(I STOKES)/dz.
So is this a set of differential equations in z only, or is there some time dependence that plays a role too ?eahaidar said:SBS and STOKES represent 2 light waves counter propagating the forward wave of index 0 which puts me in trouble since initally at z=0 I only have the forward wave
I usually use MATLAB for any simulation. I went through the equations. With the help of a colleague, we managed to reduce the coupled equations to a single equation. I will update you on that once i get to the bottom of this equation which includes the 3 variables. Again thanks for your help and would love to learn your integrator. Sounds fun to use.BvU said:(Sorry, I missed this alert during the weekend).
Program is a dynamic simulation program for the chemical industry, called aspen custom modeler. But all I use is the integrator, so I didn't mention it. It has lousy graphics, so picture is made by moving the data to excel. Also easier to do further analysis: take logarithm, fit that to a polynomial, to see if it's a simple exponential. It is not:
(##\ \ln(I_{\rm stokes} ) = -2.6356 - 0.0939 z + 0.0011 z^2\ ## )
Got the curves by doing the forward integration from z = 0 to 10. Chose C2 = I0(0) = 0.1 and played around with ISBS(0) and Istokes(0) until they ended up at the same value. I called that C1. Normally you would let the computer do the guessing (shooting method) with a reasonable efficiency.
So still no joy finding something analytical.
What tools do you have at your disposal for this ?
--