As the computation of cut-off rigidities for many positions can be highly time-consuming and since the CPU time available on SPENVIS for a single user is limited, the calculations are stopped if the program duration time exceeds a limit. This can be often the case for calculations on maps or orbit trajectories. Therefore, users are welcome to utilize SPENVIS to produce and download the macro-file but is recommended that they download the stand-alone version of Magnetocosmics to make a run.
Note that the Magnetocosmics application makes use of the Geant4 toolkit [2]. The complete Magnetocosmics user manual is available online as a PDF-document.
As the model uses a Monte-Carlo simulation-based code, execution times can be very long, certainly for cut-off calculations. The execution is limited to five minutes of CPU-time on the simulation machine. If the Magnetocosmics run exceeds this limit, the simulation will be terminated and intermediate results returned to the user.
The user can first choose the particle type: Electron Positron Proton Anti Proton Alpha He3 Deuteron Triton Ion If the particle type is Ion, the atomic and the mass number must be entered as well. The default for Ion is a C12 nucleus.
Next, one can specify the type of trajectory i.e. forward or backward trajectory. In the case of 'Single position' the user can define more than one trajectory and assign different energies or rigidities to them. When the 'Orbit' or the 'Grid' option is selected the number of trajectories corresponds to the number of orbital or coordinate grid points. Then, only one energy or rigidity value can be defined and is assumed to be the same for all the trajectories. The energies can be entered in GeV, MeV, or keV; the rigidities in GV, MV, or kV.
The last option is the selection of the colour for particle trajectory visualisation.
The position is then defined by specifying the altitude (in km or Earth’s radius, RE), longitude and latitude (both in degrees) in the chosen coordinate system.
For the calculation of cut-off rigidities and particle trajectory visualisation scenarios ('Single position', 'Orbit' or 'Grid') a user has the additional option for specifying directions.
In the case of cut-off rigidity calculatuions, the user defined directions correspond to the incident directions expressed in terms of the zenith and azimuthal angle. The coordinate system specifying the direction is always assumed to be same as the one specifying the position.
In the case of particle trajectory visualisation the user has three choices for specifying the initial direction, Predefined Pitch angle and gyration phase Zenith and azimuth angle. The predefined directions include the local zenith, the magnetic and geographic north pole axis, the direction of the Sun, the local magnetic east and the local magnetic west. For any of the above predefined direction an appropriate coordinate system is assumed. For the second option is suffice to define the pitch angle and the gyration phase. Finally, for specifying the zenith and azimuthal angle the user has also the possibility to choose a coordinate system: Geographic (GEO) Geomagnetic (MAG) Geocentric Equatorial Inertial (GEI) Geocentric Solar Ecliptic (GSE) Geocentric Solar Magnetospheric (GSM) Solar Magnetic (SM)
Note that the SPENVIS background pages contain a detailed description of all the coordinate systems used in Magnetocosmics.
The macro file spenvis_mco.g4mac contains the Geant4 Macro file. The log file spenvis_mco.g4log records the output from Magnetocosmics to stdout and stderr. The output file spenvis_mco.txt contains tabulated results according to the selected scenario (cut-off rigidities, particle trajectory or magnetic field line visualisation). The graphics file spenvis_mco.wrl shows the particle trajectories or the magnetic field .
spenvis_mco.g4mac
spenvis_mco.g4log
spenvis_mco.txt
spenvis_mco.wrl
To generate plots, select the plot type(s), options and graphics format when applicable, and click the button. The current page will be updated with the newly generated plot files.