The linearized plasma-vacuum interface problem in ideal incompressible MHD

We study the free boundary problem for the plasma-vacuum interface in ideal incompressible magnetohydrodynamics (MHD). In the vacuum region we consider the system of pre-Maxwell dynamics, while at the interface the total pressure is continuous and the magnetic field is tangent to the boundary. Under a suitable stability condition satisfied at the plasma-vacuum interface, we prove the well-posedness of the linearized problem in Sobolev spaces