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nu_rnet [2014/06/05 17:20]
schutrumpg
nu_rnet [2014/06/06 09:18] (current)
schutrumpg
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 It is possible that electron fraction Ye will affect the neutron density resulting in the abundance pattern of the r-process. It is possible that electron fraction Ye will affect the neutron density resulting in the abundance pattern of the r-process.
  
-{{:​core-collapse_figure.png?​650|Schematic representation of the evolutionary stages from stellar core collapse. (Ref. H.Th. Janka, arXiv:​astro-ph/​0612072)}}+{{:​core-collapse_figure.png?​650|}}
  
 +Fig: Schematic representation of the evolutionary stages from stellar core collapse. (Ref. H.Th. Janka, arXiv:​astro-ph/​0612072)
 =====Method and aims:===== =====Method and aims:=====
  
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 ===Reaction Network=== ===Reaction Network===
  
-Last but not least we need a reaction library. This was taken from the JINA Reaclib database. For the r-process only nucleides ​have to be considered which are stable or even more neutron rich. The proton rich nucleides ​can be neglected. In the chart of nuclei ​the considered rates look like this:+Last but not least we need a reaction library. This was taken from the JINA Reaclib database. For the r-process only nuclides ​have to be considered which are stable or even more neutron rich. The proton rich nuclides ​can be neglected. In the chart of nuclides ​the considered rates look like this:
  
 {{ :​nuclide_chart.jpg?​650 |}} {{ :​nuclide_chart.jpg?​650 |}}
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 ===Matrix Solver=== ===Matrix Solver===
  
-The standart matrix solver included in the xnet programm "​LAPACK"​ is too slow to solve a network like this. Faster solutions are sparse matrix solver. Two interfaces are included in xnet: For MA48 and Pardiso. Instructions to include these matrix solvers in the code can be found in the documentation of the code. We experienced problems for both with Linux: Pardiso should be much faster than MA48 needs a full compiled LAPACK library. This is included in the ifort compiler. Finally we succeeded in compiling Pardiso version with ifort. The program can be found here.+The standart matrix solver included in the xnet programm "​LAPACK"​ is too slow to solve a network like this. Faster solutions are sparse matrix solver. Two interfaces are included in xnet: For MA48 and Pardiso. Instructions to include these matrix solvers in the code can be found in the documentation of the code. We experienced problems for both with Linux: Pardiso should be much faster than MA48 needs a full compiled LAPACK library. This is included in the ifort compiler. Finally we succeeded in compiling Pardiso version with ifort. The program can be found in the document server.
  
 ====Results==== ====Results====
-==$Y_e=0.2$== +==$Y_e=0.15$== 
-{{ :ev20.png?400 |}}+{{ :ev15.png?400 |}}
 ==$Y_e=0.25$== ==$Y_e=0.25$==
 {{ :​ev25.png?​400 |}} {{ :​ev25.png?​400 |}}
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 {{ :​ev40.png?​400 |}} {{ :​ev40.png?​400 |}}
  
 +
 +The preliminary results show the abundances of selected nuclides. The abundances are representative for the regions of magic neutron numbers 82 and 126. The abundances in these regions should be high. For $Y_e=0.15$ only small abundances for these nuclides are present, because the seed density consisting of almost the same number of protons and neutrons is too small. For $Y_e=0.25$ we see strong abundances of these nuclides, but for higher $Y_e>​0.4$ the neutron density is too small. Thus neutron capure is too slow and the heavy elements cannot be built.
nu_rnet.1402003255.txt.gz · Last modified: 2014/06/05 17:20 by schutrumpg