Non physical fluent rate?

[mxardre]

Hi,

I am running this simulation in a thin rectangular domain filled with air mua=mus=1e-8. The boundary condition are periodic. I am very surprise to have a fluente rate of about 2500 W/cm2/W_incident for such low scattering and absorbing media. Besides the power of the light source is 40W.

Is anyone able to help me understand this value and relate it to the light source power?

All the best

%% Geometry definition
MCmatlab.closeMCmatlabFigures();
model = MCmatlab.model;

section = 0.02;
model.G.nx                = 20; % Number of bins in the x direction
model.G.ny                = 20; % Number of bins in the y direction
model.G.nz                = 1000; % Number of bins in the z direction
model.G.Lx                = section; % [cm] x size of simulation cuboid
model.G.Ly                = section; % [cm] y size of simulation cuboid
model.G.Lz                = 20; % [cm] z size of simulation cuboid


model.G.mediaPropertiesFunc = @mediaPropertiesFunc; % Media properties defined as a function at the end of this file
model.G.geomFunc          = @geometryDefinition; % Function to use for defining the distribution of media in the cuboid. Defined at the end of this m file.

model = plot(model,'G');

%% Monte Carlo simulation
model.MC.simulationTimeRequested  = 5; % [min] Time duration of the simulation

model.MC.matchedInterfaces        = true; % Assumes all refractive indices are the same
model.MC.boundaryType             = 3; % 0: No escaping boundaries, 1: All cuboid boundaries are escaping, 2: Top cuboid boundary only is escaping, 3: Top and bottom boundaries are escaping, while the side boundaries are cyclic
model.MC.wavelength               = 532; % [nm] Excitation wavelength, used for determination of optical properties for excitation light


%Radial-factorizable beam (e.g., a Gaussian beam)
model.MC.lightSource.sourceType   = 4; % 0: Pencil beam, 1: Isotropically emitting line or point source, 2: Infinite plane wave, 3: Laguerre-Gaussian LG01 beam, 4: Radial-factorizable beam (e.g., a Gaussian beam), 5: X/Y factorizable beam (e.g., a rectangular LED emitter)
model.MC.lightSource.focalPlaneIntensityDistribution.radialDistr = 0; % Radial focal plane intensity distribution - 0: Top-hat, 1: Gaussian, Array: Custom. Doesn't need to be normalized.
model.MC.lightSource.focalPlaneIntensityDistribution.radialWidth = section; % [cm] Radial focal plane 1/e^2 radius if top-hat or Gaussian or half-width of the full distribution if custom
model.MC.lightSource.angularIntensityDistribution.radialDistr = 0; % Radial angular intensity distribution - 0: Top-hat, 1: Gaussian, 2: Cosine (Lambertian), Array: Custom. Doesn't need to be normalized.
model.MC.lightSource.angularIntensityDistribution.radialWidth = 0; % [rad] Radial angular 1/e^2 half-angle if top-hat or Gaussian or half-angle of the full distribution if custom. For a diffraction limited Gaussian beam, this should be set to model.MC.wavelength*1e-9/(pi*model.MC.lightSource.focalPlaneIntensityDistribution.radialWidth*1e-2))
model.MC.lightSource.xFocus       = 0; % [cm] x position of focus
model.MC.lightSource.yFocus       = 0; % [cm] y position of focus
model.MC.lightSource.zFocus       = 0; % [cm] z position of focus
model.MC.lightSource.theta        = 0; % [rad] Polar angle of beam center axis
model.MC.lightSource.phi          = 0; % [rad] Azimuthal angle of beam center axis

model.MC.P                        = 40; %W power of light

model = runMonteCarlo(model);
model = plot(model,'MC');

%% Geometry function(s) (see readme for details)
function M = geometryDefinition(X,Y,Z,parameters)
  
  M = ones(size(X)); % fill background with cyano j=1

  disp('air bulk')
end

%% Media Properties function (see readme for details)
function mediaProperties = mediaPropertiesFunc(parameters)
mediaProperties = MCmatlab.mediumProperties;

  
  j=1;
  mediaProperties(j).name  = 'air';
  mediaProperties(j).mua = 1e-8; % [cm^-1] concentration 50x dans les nappes
  mediaProperties(j).mus = 1e-8; % [cm^-1]
  mediaProperties(j).g     = 0.8282; %cornet HDR

end