An electric sail harnesses the solar wind for propulsion. Inside the magnetosphere of Earth, the solar wind does not reach. Yet the Aalto-1 satellite intends to deorbit using an electric sail. How can the electric sail be used for deorbiting when LEO orbits are mostly or entirely within the magnetosphere? Does it operate only when the spacecraft is passing through the cusp, limiting its use to deorbiting from specific orbit?
The relevant text on Wikipedia is uncited and confusing at best, containing two mutually conflicting statements:
The electric sail cannot be used inside planetary magnetospheres because the solar wind does not penetrate them, allowing only slower plasma flows and magnetic fields. Inside a planetary magnetosphere, the electric sail may function as a brake, allowing deorbiting of satellites.