Location of the collisionopause assuming an outgassing rate of 6 × 10²⁷ s⁻¹, the value estimated for 67P during the Rosetta excursion. The dashed lines give the location using Eq. (2), while the solid lines include the ion velocity correction given in Eq. (6). A neutral outgassing velocity of 600 m s⁻¹ is assumed. The collisionopause location was observed by RPC-IES at 500–700 km, or the upper range using the Mendis cross sections (gray band). The blue shaded region indicates the location where the ion and neutral velocities are the same. The tan box indicates the range of IES ion energy, but this range is extended toward lower energies because of the negative spacecraft potential.