Differential intensity integrated over the mission duration and forecast.

This site provides access to the main HelMod web calcultor - which is an application of the latest available HelMod Code - for unregistered users, e.g.,

HelMod data sets and results can be freely downloaded or copied. However, we strongly suggest user to provide an appropriate acknowledgment and/or citation, e.g., see  Citations or Bibliography  pages.

How to use this HelMod Calculator

This tools evaluates the modulated spectrum at Earth orbit for theorical LIS evaluated with GALPROP. The particle transport is described using the Helmod Model. For information about the computation method please refear to Monte Carlo Integration page.

The input parameters and options for the tool are described below. Once the input form has been completed,  "Submit" button will start the calculation and open the "Results" page (allow for pop-up in your browser settings).

Solar Modulation Model

The website is always updated with the latest HelMod version available, as indicated in the output result.
Previous version remains available for a limited period during updating.

Expected Mission Duration/ Past Missions

User can select either the time interval for the interested simulation or refer to a standard published dataset (e.g., AMS-02).

• Expected mission  duration: allow to select a single Galactic Cosmic rays species and the expected duration of the mission. By default the module evalute the modulated spectrum for a single Carrington rotation containing the "begin of the mission" value. To evaluate the average modualted spectra over the entire period of the mission, check the box "Average over the entire period" and select the date of the end of the mission.
• Past missions: allow to compute modulated spectra referring to period and GCR species described in  standard published datasets. User may select, in order, the Experiment (e.g. AMS-02), then the GCR species (e.g. Proton) and finally the publised dataset.

Display Options

• x-axis value: Select if output result should be computed in Particle Rigidity [GV] or in Kinetic Energy per nucleon [GeV]. If "auto" is selected, the system will choise the best one for the selected dataset.
• Addittional modulation models: compute the modulated spectrum using  ISO 15390, DLR version or  ISO 15390 models. This features is not available for forecast simulations.

Result

The result page contains the figure of modulated spectrum and and correspondent tabulated data.
Text file and numpy/python archive are also available for Download.

For expert users it is available the possiblity to modify some relevant HelMod parameters.

Available parameters may change for different HelMod version. For latest default parameters please refer to Current and History of default parameters page.

HelMod provide optimized LIS developed with GALPROP and presented on international journals, Expert users may load their own develped LIS. HelMod accept the following formats:

• GALPROP fits file (*.gz extension). The fits must contain at least the computed LIS for the Galactic Cosmic Rays particle species to be modulated. The Module evaluate the LIS for modulation as the sum of modulated primary spectrum with  secondaries and modulated isotopes.
• plaintext file. User can provide a txt file for LIS with the follow characteristics:
• The file should have a mime type 'text/plain' (Checkout this list for allowed extensions).
• The file must contains two columns only: one for kinetic energy per nucleon [GeV], the second for the LIS flux [ (m$$^2$$ s sr GeV)$$^{-1}$$].
• The file can contains comments. Line starting with '#' character will be ignored.

It should be remarked that data generated by using the Calculator may be used by HelMod developers for statistical purpose.

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.