This is the HelMod Code Web application. Unregistered users can freely access to Heliospheric Modulation calculator for available experiments datasets.

The following link give access to Calculators:

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.

The data generated by using the Calculator may be used by HelMod developers for statistical purpose.

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).

Input Parameters:

- Galactic Cosmic Rays particle species
- Experiments datasets
- HelMod Parameters 

Galactic Cosmic Rays particle species

In the HelMod Calculator, using the drop down menu, the user can select the species Galactic Cosmic Rays to be modulated.

Experiments datasets

In the HelMod Calculator it is possible to specify Experiment dataset that the uses wish to compare with the simulation. The Experiment is required to design the Rigidity binning, Moreover, since solar modulations change in time as the soalr activity, this choise specify the heliosphere parameters for the corresponding period.

List of available Experiments


To evaluate the Modulated spectrum it is mandatory to load a LIS in the format of 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 primary spectrum with secondaries and isotopes.

From Version 3.0.1 HelMod accept also LIS in plaintext mode. User can provide a txt file for LIS with the follow characteristics:

  1. The file should have a mime type 'text/plain' (Checkout this list for allowed extensions).
  2. 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)\(^{-1}\)].
  3. The file can contains comments. Line starting with '#' character will be ignored.



The result page contains the modulated spectrum and relative difference with respect experimental data. Results are provided as image, text file and numpy/python archive.


Default parameters and Example

Default parameters provided best results using the InBuilt Default LIS. The Default LISs for Proton, Antiproton and Helium were obtained using a state-of-art version of GALPROP  where a smoothing in the injection spectra was introduced, as discussed in Boschini et al 2017a and Boschini et al, 2017bb. The Combination of both allow the user to have the best agreements between simulated modulated spectrum and Experimental Data. 



BoschiniEtAlAdvSR2017 Boschini, M.J., Della Torre, S., Gervasi, M., La Vacca, G. and Rancoita, P. G. (2017a) Propagation of Cosmic Rays in Heliosphere: the HelMod Model Accepted for publication in Advances in Space Research. ArXiv:1704.03733, DOI: 10.1016/j.asr.2017.04.017
BoschiniEtAlApJ2017 Boschini, M.J., Della Torre, S., Gervasi, M., Grandi, D., Johannesson, G., Kachelriess, M., La Vacca, G., Masi, N., Moskalenko, I. V., Orlando, E., Ostapchenko, S.S., Pensotti, S., Porter, T. A., Quadrani, L., Rancoita, P. G., Rozza, D. and Tacconi, M. (2017b) Solution of Heliospheric Propagation: Unveiling the Local Interstellar Spectrum of Cosmic Rays Species  Astrophysical Journal, 840:115.