A more detailed description of the montecarlo process

[wkerzendorf]

After talking to Frederik this morning I whipped this up to give a more detailed description of the montecarlo process to the users. @ssim please confirm that this is correct

@fredRos

[landscape-bot]

Code quality remained the same when pulling 7136c45 on wkerzendorf:docs/scattering_description into 8ca74ec on tardis-sn:master.

[ssim]

Hello:

Mostly ok - but we don’t (shouldn’t at least!) assume emission is “isotropic in angle for a half-sphere” - we should be using mu = sqrt(z) [as in Abbott & Lucy 1985], which is not isotropic.

Typically, packets do work on the ejecta and so we expect on average that they lose energy during interactions.

[coveralls]

Coverage remained the same at 55.27% when pulling 7136c45 on wkerzendorf:docs/scattering_description into 8ca74ec on tardis-sn:master.

[wkerzendorf]

@ssim well interestingly enough the escaping packets seem to gain energy.
So I agree that mu=sqrt(z), but presumed that means they are isotropically distributed in theta (mu = cos(theta)) - but maybe that is wrong.

[ssim]

No - isotropic would not be sqrt! Isotropic would be mu = z (for positive hemisphere).

Overall, work should be done on the ejecta, but it may be that that mainly shows up in the backscattered packets. Also may depend on which frame you calculate the energies in.

[wkerzendorf]

@ssim I just changed the wording. Let me know if we are ready to merge this.

[landscape-bot]

Code quality remained the same when pulling 4cf99ff on wkerzendorf:docs/scattering_description into 8ca74ec on tardis-sn:master.

[coveralls]

Coverage remained the same at 55.27% when pulling 4cf99ff on wkerzendorf:docs/scattering_description into 8ca74ec on tardis-sn:master.