Coded-Aperture Technique for Magnetosphere Imaging - Advantages and Limitations

The imaging of magnetosphere in energetic neutral atom (ENA) fluxes is recognized as a powerful experimental tool in the study of global magnetospheric processes. Intensity of ENA fluxes is typically very low. ENA's cannot be collected and concentrated by diffracting and refracting elements as it is done in optics, and therefore an imaging system on the basis of the pinhole camera should be used. There were several suggestions to use a coded-aperture technique to enhance geometrical throughput and, consequently, sensitivity of the instruments. The coded-aperture technique is reviewed and its application to the planetary magnetosphere imaging is considered. Computer simulation demonstrates advantages and limitations of the technique and promising applications are identified.