ASPERA-3: Energetic Neutral Atom Imaging


Energetic Neutral Atom (ENA) Imaging

Basic Concept

The co-existence of an energetic charged particle population (solar wind, magnetospheric plasma) and a planetary neutral gas leads to interaction, e.g., through charge-exchange:

A+(energetic) + P(cold) => A(energetic) + P+(cold)

In contrast to charged particles, ENAs are no longer influenced by electromagnetic fields and propagate on straight paths from the source to the observer. Directional detection of ENAs yields a global image of the interaction and by complex inversion techniques properties of the source populations can be deduced.

ENA production mechanisms in space plasmas comprise:

ENA Imaging Applications

The > IMAGE mission successfully proved that ENA imaging can provide global views of plasma processes (substorm particle injections, ring current distribution and dynamics) in the Earth's Magnetosphere.

The >MIMI instrument on Cassini provided ENA images of the Jupiter - Io Torus system.

The simulated ASPERA-3 ENA response shows that the solar wind - exosphere interaction processes at Mars can be globally imaged in ENA.

© 2006, Max-Planck-Institut für
Sonnensystemforschung, Lindau