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 Solar Modulator

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).

Results with this modulator have to be considered preliminary since sistematic crosscheck with experimental data is in progress.

Input Parameters:

- Galactic Cosmic Rays particle species
- Carrington rotation


Galactic Cosmic Rays particle species

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

Carrington Rotation

In the HelMod Solar Modulator it is possible to specify the period for which the solar modulation would be evaluated. The choice specify the heliosphere parameters for the corresponding period. Solutions are provided using the AMS-02 rigidity binning from 1 GV to 1 TeV.

List of available Periods


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. Results are provided as image, text file and numpy/python archive.

Default parameters and Example

Default parameters provided best results according to proton spectra comparison with experimental data (see Boschini et al 2017). Example of preliminary LIS for ions are provided in TXT format.



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. (2017) Solution of Heliospheric Propagation: Unveiling the Local Interstellar Spectrum of Cosmic Rays Species  Astrophysical Journal, 840:115.