NE410/510 - Lecture 7: The Moments of the Boltzmann Transport Equation

In this lecture we prep for deriving the Neutron Diffusion Equation by taking the 0th and 1st moments, with respect to Omega, of the Boltzmann Transport Equation.

[@shaun1098]

Hello, could you give any help as to why omega*omega' = mu = cos(theta). And similarly, why omega = cos(theta)ux + sin(theta)cos(phi)uy....
Wait haha, just by thinking just then, omega*omega' = cos(theta) ->> it's just the basic dot product rule after a collision, of course ahahah.
But still for = cos(theta)* + sin(theta)cos(phi)*.... what does this mean exactly? Is it a unit of solid angle with area = 1? And if so how is it derived?
= unit vector of a.
Thanks, Nuclear Engineering student from UK, really useful and jam-packed lectures! I wish my course went into as much detail as it does here. Thankfully these vids are free haha!

[@benjaminshatokhin4725]

you can find it by looking up cartesian, polar coordinate conversion.en.wikipedia.org/wiki/Polar_coordinate_system, for more info.