Phase‐steepened Alfvén waves, proton perpendicular energization and the creation of magnetic holes and magnetic decreases: The ponderomotive force

Solar wind protons detected within Magnetic Holes (MHs) and Magnetic Decreases (MDs) are found to be preferentially heated perpendicular to 0 . The MHs/MDs are associated with the phase‐steepened edges of nonlinear Alfvén waves. The proton anisotropies can lead to the proton cyclotron and mirror mode plasma instabilities. We examine the Ponderomotive Force (PF), a phenomenon due to wave pressure gradients, and show that for this plasma regime and for phase‐steepened Alfvén waves, the PF proton acceleration/energization will primarily be orthogonal to B 0 . It is suggested that accelerated ions create the MHs/MDs by a diamagnetic effect.