- #1
FourierFaux
- 98
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Hello folks, this is my first post. I'm not quite sure that I fully understand the idea of a random walk of a photon that is generated at the core of a star.
I've read this:
http://www3.wooster.edu/physics/jrIS/Files/Walker_Web_article.pdf
My understanding of the theory is this:
A photon gets generated with some initial direction in the star. After traveling some distance (which can be probabilistically determined) is absorbed, then reradiated in some perfectly random direction (any number between 0 and 360 degrees in the theta and phi angles)?
I'll come at this at a different perspective, optics: normal experience playing around with a laser pointer. I point the laser at the wall. Note, the light from the laser pointer doesn't quite do it's random walk in the same way that the photon in the star does (again, unless I'm completely misunderstanding the type of random walk in the star). I point at a position on the wall, and the light from the laser forms a point. If the random walk were completely random in this case, then the light from the laser could've ended up anywhere. What happens with the light from the laser pointer instead is that the light get's absorbed by the molecules in the air then re-emitted opposite the direction of incidence. Shouldn't this happen in a star too?
1) o --> O 2) <O> 3) O -- o -->
Another aspect of common experience: the index of refraction for light in air is strongly dependent upon it's temperature (I don't know if this remains true for plasmas). If variations in the temperature within the star were great enough on a specific scale to produce a difference in the index of refraction, then I could see a variation on the random walk behavior that's described in the theory.
Also, there are some large scale convection structures within stars. I could see "reflection" off of these... but it would only be speculation.
I'm probably way off base with one of my assumptions. Help me understand this?
I've read this:
http://www3.wooster.edu/physics/jrIS/Files/Walker_Web_article.pdf
My understanding of the theory is this:
A photon gets generated with some initial direction in the star. After traveling some distance (which can be probabilistically determined) is absorbed, then reradiated in some perfectly random direction (any number between 0 and 360 degrees in the theta and phi angles)?
I'll come at this at a different perspective, optics: normal experience playing around with a laser pointer. I point the laser at the wall. Note, the light from the laser pointer doesn't quite do it's random walk in the same way that the photon in the star does (again, unless I'm completely misunderstanding the type of random walk in the star). I point at a position on the wall, and the light from the laser forms a point. If the random walk were completely random in this case, then the light from the laser could've ended up anywhere. What happens with the light from the laser pointer instead is that the light get's absorbed by the molecules in the air then re-emitted opposite the direction of incidence. Shouldn't this happen in a star too?
1) o --> O 2) <O> 3) O -- o -->
Another aspect of common experience: the index of refraction for light in air is strongly dependent upon it's temperature (I don't know if this remains true for plasmas). If variations in the temperature within the star were great enough on a specific scale to produce a difference in the index of refraction, then I could see a variation on the random walk behavior that's described in the theory.
Also, there are some large scale convection structures within stars. I could see "reflection" off of these... but it would only be speculation.
I'm probably way off base with one of my assumptions. Help me understand this?
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