It is currently Sun Nov 28, 2021 4:55 am

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 2 posts ] 
Author Message
PostPosted: Fri Aug 30, 2013 7:18 pm 
Offline

Joined: Tue Nov 27, 2012 7:41 pm
Posts: 17
I'm curious to discuss such kind of general theoretical questions: what can be said about a uniqueness of a solution of the transport equation, which GALPROP looks for with boundary conditions specified? Was this question intentionally investigated?

And what is the justification of the choice of boundary conditions? Saying by another words, why do we use specifically these boundary conditions? Particularly, it's slightly unclear for me how we can solve the equation without imposing anything for the momentum variable (as manual says)? What's about initial conditions?

_________________
Andrey Egorov, LPI


Top
 Profile  
 
PostPosted: Sat Oct 26, 2013 11:32 pm 
Offline

Joined: Wed May 17, 2006 7:02 am
Posts: 285
Location: MPE Garching
The spatial boundary conditions are the standard assumptions of zero CR density at the halo boundaries. This is actually not very physical. Free escape at the boundaries (which is not the same thing) would be more appropriate. I am going to implement this soon.

The momentum boundary conditions are indeed not rigorous, and GALPROP relies on the assumption that the momentum range is chosen large enough for this not to be important. At low energies with energy losses, the flow is only from high to low, so it is no problem. For reacceleration it could be a problem. Same for momentum advection. These issues deserve attention.

_________________
Andy Strong, MPE


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 2 posts ] 

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group