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How does the magnetopause form the outer boundary of the magnetosphere?

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Diagram of Earth's atmosphere layers-troposphere, stratosphere, mesosphere, and thermosphere-showing how temperature and air pressure change with increasing altitude, with key features like the ozone layer and pressure percentages at various heights. — Ionosphere and magnetosphere The layers of Earth's atmosphere, with a yellow line showing the air temperature at various heights.

The magnetopause serves as the outer boundary of the magnetosphere by acting as an equilibrium region where the pressure of the solar wind is balanced by the geomagnetic field.123

Located approximately 10 Earth radii (about 65,000 km) from the planet on the dayside, this boundary forms through the interaction of these two opposing forces. The process is driven by the magnetopause current (or Chapman-Ferraro current system), which flows in a thin sheet. When solar wind particles encounter Earth’s magnetic field, they are deflected by the Lorentz force, creating an eastward electric current in the equatorial plane.134

This current system effectively confines Earth’s magnetic field within the magnetopause, preventing it from expanding indefinitely. While it marks the outer boundary, the magnetopause is not an impenetrable wall; plasma particles from the solar wind can leak through it into the magnetosphere, and the boundary itself is characterized by a thickness of approximately 100 km.4123