CR interaction with solar enviroment simulation

I am quite new FLUKA and currently trying to simulate the cosmic ray iteraction with the solar environment inorder to study the gamma ray emission coming from sun. I have scrolled through the FLUKA courses from 2019 and 2021. I have some basic questions to discuss and gradually build upon that.

  1. The current geometry I am using is very simple - Concentric spheres with appropriate materials denoting different layers of the solar environment.

  2. I want to simulate an isotropic GCR source, a spherical source surface concentric to the sun atmosphere. I have been going into rabit holes regarding the ways to do it. I have familiarised myself witht the new_source routine. The thing I am confused about is where the default GCR-SPE cards along with SPECSOUR card can be used to simulate what I am trying to do or are they only specific to studies with the Earth’s atmosphere?

  3. As a preliminary step, to observe the gamma ray fluence crossing a particular boundary defined by USERBDX after the CR interaction, what other cards (Physics cards, threshold cards etc) needs to be activated?

Thanks a lot

Dear @amrit.p.nayak ,

From my understanding of the description of your problem, you can use the SPECSOUR and GCR-SPE cards to achieve your goal. You can set up the SPECSOUR card by setting the particle injection radius in WHAT(2). You can have a look at section 16.7 of the FLUKA manual for more details.

Given that you are not using the standard FLUKA geometry of the Earth atmosphere, I strongly recommend to use the option NO-NORM in the GCR-SPE card. This option will get rid of the built-in normalization of the Earth atmosphere’s layers and you can always apply the proper normalization in post-process. Please note that for running the simulation with the NO-NORM option, a folder called gcr must be present in the folder where you run your simulation: the grc folder must contains all the *.spc, renamed as follows:


Other physics/transport cards will mainly depend on your physics problem.

Finally, for GCR applications make sure you link your executable to DPMJET.


Thanks a lot for getting back to the queries. At the moment, this solution worked out for me. I would post further question in this topic as I proceed with further simulation.

Best Wishes