The ASPERA-4 instrument on board the Venus Express spacecraft offers for the first time the possibility to directly measure the emission of energetic neutral atoms (ENAs) in the vicinity of Venus. When the spacecraft is inside the Venus shadow a distinct signal of hydrogen ENAs usually is detected. It is observed as a narrow tailward stream, coming from the dayside exosphere around the Sun direction. The intensity of the signal reaches several 105 cm- 2 sr- 1 s- 1, which is consistent with present theories of the plasma and neutral particle distributions around Venus.
- Solar wind-planetary atmosphere interaction
- Venus exosphere
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science