Plasma environment at Venus

This diagram shows the plasma environment of Venus as determined by Venus Express (plasma is a gas of charged particles surrounding planets).
All parameters noted in the figure are measured on a regular basis by the magnetometer (MAG) and the ASPERA-4 instruments on board ESA’s
Venus Express, in three distinctly different regions: the unperturbed solar wind (sw), the plasma sheath (ps) and the induced magnetosphere/tail (t).

The boundaries determined by the two instruments are shown approximately to scale. Oxygen ions are observed at high concentrations around the
terminator and at lower concentrations well into the tail, indicating escape from a specific source region. Helium ions (He+) show similar behaviour,
whereas hydrogen ions (H+) are seen to be much more evenly distributed around the planet (RV is the radius of Venus).