magnetopause
![magnetosheath, magnetopause, and bow shock](http://178.128.105.246/cars-http-www.daviddarling.info/../../images/magnetosheath.jpg)
A magnetopause is the boundary between a planet's magnetosphere and the magnetic field of the solar wind. It forms at a distance where the solar wind dynamic pressure equals the magnetic pressure of the planet's field. In the case of Earth, this is typically 8 to 11 Earth radii upwind, depending on solar wind conditions.