ESA Science & Technology - Close up of magnetic fields

Illustration of quasi-parallel (top) and quasi-perpendicular (bottom) magnetic field conditions at a planetary bow shock. Under quasi-parallel conditions, the magnetic field is roughly pointing toward the shock surface, almost parallel to a vector at right angles to the shock front (red arrow). Under quasi-perpendicular conditions, the magnetic field is close to aligned with the shock surface, that is, almost perpendicular to the shock vector.