Properties of A Supercritical Quasi-Perpendicular Interplanetary Shock Propagating in Super-Alfvénic Solar Wind: from MHD to Kinetic Scales

We investigate the properties of an interplanetary shock (M_A=3.0, θ_Bn=80°) propagating in Super-Alfvénic solar wind observed on September 12^th, 1999 with in situ Wind/MFI and Wind/3DP observations. Key results are obtained concerning the possible energy dissipation mechanisms across the shock and how the shock modifies the ambient solar wind at MHD and kinetic scales:  (1) Waves observed in the far upstream of the shock are incompressional and mostly shear Alfvén waves.  (2) In the downstream, the shocked solar wind shows both Alfvénic and mirror-mode features due to the coupling between the Alfvén waves and ion mirror-mode waves.  (3) Specularly reflected gyrating ions, whistler waves, and ion cyclotron waves are observed around the shock ramp, indicating that the shock may rely on both particle reflection and wave-particle interactions for energy dissipation.  (4) Both ion cyclotron and mirror mode instabilities may be excited in the downstream of the shock since the proton temperature anisotropy touches their thresholds due to the enhanced proton temperature anisotropy.  (5) Whistler heat flux instabilities excited around the shock give free energy for the whistler precursors, which help explain the isotropic electron number and energy flux together with the normal betatron acceleration of electrons across the shock.  (6) The shock may be somehow connected to the electron foreshock region of the Earth’s bow shock, since Bx > 0, By < 0, and the electron flux varies only when the electron pitch angles are less than PA = 90°, which should be further investigated. Furthermore, the interaction between Alfvén waves and the shock and how the shock modifies the properties of the Alfvén waves are also discussed.