The SDE integration with HelMod results in a quite expensive effort from the computational point of view since,
to minimize the uncertainties, an huge amount of event should be integrated from Earth to heliosphere boundary.

Monte Carlo integration allows us to evaluate the normalized probability function $$G(R_0|R)$$ that a particle observed at Earth with rigidity $$R_0$$ entered into the heliosphere with rigidity $$R$$.
Thus, the modulated spectrum at specific energy $$R_0$$ is proportional to:
\label{eq::PyMod_modulation}
J_{mod}(R_0)= \int_0^\infty J_{LIS}(R)G(R_0|R)dR.

Once that $$G(R_0|R)$$ was evaluated, using the numerical approximation, it is possible to apply the modulation directly to LISs provided by GALPROP.

The effect of propagation in heliosphere is then evaluated using a normalized probability function pre-evaluated with HelMod using parameters described in previous section.
We developed a python script that read GALPROP output and provide modulated spectrum for periods of selected experiments.

HelMod data sets and results can be freely downloaded or copied. However, the user should make the appropriate acknowledgment or citation, e.g., see  Citations or Bibliography  pages.

### How to install and configure (under Review)

install python (>=2.7) packages

• pyfits
• scypy >=0.17.0
• numpy >=1.10
• wget
• matplotlib

Download  last Python Module and the desidered Archive. The archive is provided in tgz format, thus it needs to be first unpacked with the command tar -xvzf <ArchiveName>.tgz

#### The archive structure:

An Archive contains msut contains the follows files:

• ExpList.list   : List of nuclei and isotopes simulated (to not modify)
• ExpList_Plot.list  : List of nuclei available in the archive, reference and plots properties (do not modify first ant second columns, the other can be updated to modify the output plots)
• ParameterSimulated.list : list of folders in the form RawPar_HelMod4_XX, This should contain  (at least one line should start with '+', if not, please add it to first line)
• ParameterSimulated_DB.list: list of folders in the form RawPar_HelMod4_XX, with description
• Version.txt : Version notes
• DataTXT : experimental binnign used for simulations
• RawPar_HelMod4_00 : HelMod simulations files

#### How to use the module:

To use the module one must know the path of the archive. For e.g. <ArcPath>=/home/test/Archive1  as the palce where Archive1.tgz was unpacked.

The basic command to get Solar modulated spectrum is:python SolarModulation_Galprop_<version>.py -a <ArcPath> <GALPROPFits.gz> <ExpNameKey>

where <ExpNameKey>  is the key name that identify nuclei and time/experiment to be simulated.

The list of available <ExpNameKey>  may be found in the file ExpList_Plot.list or using the command-line python SolarModulation_Galprop_<version>.py -a <ArcPath> -l.

It is possible to avoid the -a optiond defining the system key export HelMOD_RAW_FILES=<ArcPath>.

other possible options are:

• --MakePlot : Create a Plot in png format
• --NoExpData : display simulation and LIS only, This  is mandatory if you are using one of Solar Modulater Archive.
• --joinLIS  : Sum the Isotopes LIS of the selected nucleous (ex. proton, Deuterium,..) and apply the modulation to the summed spectra. The result is provided in Kinetic Energy per nucleon (GeV/n)
• --joinIsotope : apply different modulation for different Isotopes, then Sums the resultung modulated spectra. The result is provided in Rigidity (GV).
• -p <PAR_SET_NAME> : specify a different simulation for this nuclei. The list of availabel siulation can be seen in ParameterSimulated_DB.list or python SolarModulation_Galprop_<version>.py -a <ArcPath> --ListParSet
• -t      : allow to use a TXT file for Input LIS instead of Galprop File.
• --PrintLIS  :  Print LIS used for Modulation (note that if --joinIsotope is Activeted output LIS is the sum in Rigidity of all isotopes)
• --ExtraSource_GeV <SOURCE_File>:  specify an extrasource to be added to LIS. File must be two column and expressend in GeV/nuc

#### LIS in text format

User can provide a txt file for LIS with the follow characteristics:

• The file must be a text file.
• The file must contains two columns only:
1. one for kinetic energy per nucleon [GeV]
2. the second for the LIS flux [ (m$$^2$$ s sr GeV)$$^{-1}$$].
• The file can contains comments. Line starting with '#' character will be ignored.