Neutral Particle Detector (NPD)

     The NPD sensor extends the ENA images in two new dimensions, mass and energy.  The energy spectra produced by this sensor supplies direct information about the temperature and plasma bulk velocity in the interaction region and the magnetospere.

     By remotely measuring the energy of the accelerated planetary ions and global configuration of the escaping plasma, the NPD and NPI sensors allow a determination of the total ion outflow which is the crucial parameter in the understanding of the atmospheric erosion process under the solar wind action.