On Local Well-Posedness of 3D Ideal Hall–MHD System with an Azimuthal Magnetic Field
摘要
In this paper, we study the local well-posedness of classical solutions to the ideal Hall–MHD equations whose magnetic field is supposed to be azimuthal in the L2-based Sobolev spaces. By introducing a good unknown coupling with the original unknowns, we overcome difficulties arising from the lack of magnetic resistance, and establish a self-closed Hm with (3 ≤ m ∈ ℕ) local energy estimate of the system. Here, a key cancellation related to θ derivatives is discovered. In order to apply this cancellation, part of the high-order energy estimates is performed in the cylindrical coordinate system, even though our solution is not assumed to be axially symmetric. During the proof, high-order derivative tensors of unknowns in the cylindrical coordinates system are carefully calculated, which would be useful in further researches on related topics.