Neutral atom imaging of the ring current is one of the scientific objective of the IMAGE mission. Energetic neutral atoms (ENA) emit from the ring current as the energetic ions charge exchange with the hydrogen geocorona. The ENA fluxes observed in the magnetosphere are line-of-sight integrations of the ion fluxes with folding in the hydrogen density and the charge exchange cross section.
Two particle detectors on IMAGE are designed to measure ENA from the ring current. Medium-Energy Neutral Atom (MENA) imager and High-Energy Neutral Atom (HENA) imager measure neutrals from 1-30 and 10-200 keV, respectively. The ring current model of Fok et al. is used to generate ENA images that MENA and HENA would see. Instrument counts along the IMAGE orbit are generated according to the instrument parameters of MENA and HENA. We have simulated the magnetic cloud event on October 18-19, 1995. In this study, magnetic dipole field is assumed and the convection electric potential and boundary ion fluxes are specified by the Magnetospheric Specification and Forecast Model. Ion loss along the drift path due to charge exchange with the neutral hydrogen is included.
In order to determined how much ring current intensity and pitch angle information can be obtained from this imaging technique, the simulated ENA images are deconvolved and compared with the original ion fluxes produced by the ring current model. A deconvolution scheme has been developed by Dr. Joe Perez at the Auburn University. Click here for more information.