Help: Jovian trapped particle radiation

Overview

SPENVIS can run the newly developed JOsE Jupiter trapped radiation model over a spacecraft trajectory. This feature is available for advanced users only.

The input parameters and options for the trapped particle radiation models are described below. When the input form has been completed, pressing the button will start the calculation and bring up the "Results" page.

Warning: using these buttons deletes all existing output from the trapped radiation models and from any model that uses this output, in order to ensure consistency in the outputs.

The JOSE model

JOSE is a new JOvian Specification Environment model, based on all relevant data measured by interplanetary missions during their passage in Jupiter's magnetosphere, in order to obtain an easy-to-use engineering model for Jupiter's environment. The JOSE model allows calculating fluxes in the Jovian magnetosphere for 5 species: electron, proton, carbon, oxygen and sulphur (ion fluxes are calculated from the HIC model^[1] which is implemented in JOSE).

The range of the JOSE model extends from the planet up to a radial distance of 100 R_J in the equatorial plane and ±100 R_J away of the magnetic equator. However, there is a region where JOSE is not available at all: r>15 R_J and L>20, with r the radial distance in the equatorial plane and L McIlwain's magnetic parameter.

Concerning the energy coverage, it is typically 0.02–1000 MeV for electrons and 0.1–1000 MeV for protons. If the selected energy or selected radial distance is outside the coverage of JOSE, fluxes are set to -1.0E+31.

JOSE model contains a mean model and a model including confidence level for protons and electrons. The statistical study for the confidence levels is based on Galileo data, which is the only one data set usable from a statistical point of view. Confidence level is an input of JOSE to be selected by the user. A confidence level 80% means that 80% of Galileo data is lower than the fluxes predicted by the JOSE model. Please not that a confidence of 0.5 does not correspond to mean fluxes. The mean JOSE model results correspond, depending on radial distance and energy selected, to results from the JOSE model with a confidence level between 0.7 and 0.8.

For detailed information about the mathematical function performed by and use of the software, the reader is referred to the Technical Notes TN1^[2] and TN-CCN^[3] and the Software Design Document^[4]. The validation of the model is discussed in Technical Note TN3^[5].

Heavy Ion Models

Two Jovian trapped heavy ion models are included in Spenvis:

the 2011 JPL Jovian equatorial heavy ion model^[6];
and the JPL-2003 model ^[7,8].

The models are selected via the pull down menu interface:

The IEM Model

The Interplanetary Electron Model (IEM) was developed under ESA contract by Cosine Science & Computing BV in collaboration with the University of Surrey^[9]. This model is based on observations of electrons in interplantary space (mainly near 1 AU). The most important contribution to interplanetary electrons arises from the intense emissions from the Sun during solar energetic particle events. However, at quiet times, Jupiter is the dominant source. Hence, IEM includes a model of Jovian electrons and takes into account the diffusion processes that transport electrons through the heliosphere. The IEM model was evaluated^[10] to give an estimate of the electron flux just outside the Jovian magnetosphere. This provided a power law fit to the spectrum: F(E) = 21.826 E^-1.5705 cm^-2 s^-1 sr^-1 MeV^-1
Or in the integral form: F(E) = 21.826 E^-0.5705/0.5705 cm^-2 s^-1 sr^-1

There are several options for combining the Jose spectrum and the IEM spectrum:

Option 1. does not calculate the IEM flux spectrum, only Jose fluxes for electrons are calculated.
Option 2. the Jose spectra and IEM spectrum are added.
Option 3. the maximum flux for the two models is used.
NOTE: this method may result in inconsistencies between the differential and integral flux spectra

The default option is to not include the IEM flux spectrum.

Spacecraft coordinates

In order to run the JOSE models, a spacecraft trajectory is needed. If no trajectory has been generated yet, the orbit generator should be run first. Alternatively, a spacecraft trajectory can be uploaded.

Results

The JOSE models produce the files listed in the table below. A description of the file formats can be brought up by clicking on their description in the table.

The report file spenvis_trj.html contains the input parameters and summary tables. The orbit averaged spectra for trapped protons, electrons and ions are stored in the spenvis_tri.txt file. The spectrum files spenvis_sp*.txt contain, for each orbital point, the full spectra of trapped protons, electrons, and ions, respectively.

**Output files generated by the JOSE models**
File name	Description
`spenvis_trj.html`	Report file
`spenvis_ppeakfl.html`	Report file specific for proton peak fluxes
`spenvis_epeakfl.html`	Report file specific for electron peak fluxes
`spenvis_cpeakfl.html`	Report file specific for Carbon peak fluxes
`spenvis_opeakfl.html`	Report file specific for oxygen peak fluxes
`spenvis_speakfl.html`	Report file specific for sulphur peak fluxes
`spenvis_epeakfl.html`	Report file specific for electron peak fluxes
`spenvis_tri.txt`	Orbit averaged spectra
`spenvis_spp.txt`	Proton spectra for each orbital point
`spenvis_spe.txt`	Electron spectra for each orbital point
`spenvis_spc.txt`	Carbon spectra for each orbital point
`spenvis_spo.txt`	Oxygen spectra for each orbital point
`spenvis_sps.txt`	sulphur spectra for each orbital point

To generate plots, select the plot type(s), options and graphics format, and click the or button. The current page will be updated with the newly generated plot files.

The button calls up the output page for consecutive runs of multiple models. This button only appears when the trapped radiation models have been included in the combined model run selection.