Two sets of input parameters are required for EQUIPOT, to define the spacecraft environment and the spacecraft materials, respectively.
When the input form has been completed, pressing the button will start the calculation and bring up the "Results" page.
The user can choose between a low-altitude (LEO) environment or a high-altitude (GEO) environment. For both altitude regimes, the charged particle environment has to be specified. For low altitudes, the ram/wake configuration has to specified as well. When ram or wake effects are taken into account, the spacecraft altitude (from which the velocity is calculated) and the angle of attack on the isolated patch need to be entered.
In order to characterize the plasma environment, a number of pre-defined environments can be chosen (the environment parameters are listed in the report file), or the environment parameters can be specified by explicitly defining thermal spectra and energy spectra (individual spectra are activated by checking the corresponding check boxes). Three thermal spectra can be defined for electrons and for ions by entering a density and temperature, and a mean mass for ions. The energy spectra are entered in a two column format in the corresponding text areas, in order of increasing energy. If a user defined environment is selected, at least one thermal spectrum for electrons and ions each should be specified.
The first three parameters (relative permittivity, thickness and conductivity) only apply to non-conductive materials and will thus not appear for conductive materials. The parameters defining the electron induced secondary electron emission depend on the SEE formula that is selected. The menu for the structure material includes an option to fix the structure potential. In this case, no material parameters are required.
If a conductive patch material was selected, the properties of an intermediate insulator (thickness, conductivity, and relative permittivity) have to be specified in an additional table that does not appear when the patch material is an insulator.
The report file spenvis_epp.html is a printable file containing the input parameters and summary tables. The spenvis_epo.txt file is used by the plotting routines to produce graphical output.
spenvis_epp.html
spenvis_epo.txt
To generate plots, click the appropriate check boxes, select the plot options and graphics format, and click the button. The current page will be updated with the newly generated plot files.