Waves upstream of interplanetary shocks
- 1Universidad Nacional Autonoma de Mexico, Instituto de Geofisica, Ciencias Espaciales, Mexico City, Mexico (xbc@geofisica.unam.mx)
- 2The Blackett Laboratory, Department of Physics, Imperial College London, London SW1234, UK
- 3School of Physics and Astronomy, Queen Mary University of London, London E31NS, UK
- 4Swedish Institute of Space Physics, Uppsala, Sweden
- 5Department of Physics and Astronomy, University of Turku, Turku, Finland
- 6NASA Goddard Space Flight Center, Greenbelt, Maryland, USA.
Interplanetary (IP) shocks can be driven in the solar wind by fast coronal mass ejections and by the interaction of fast solar wind with slow streams of plasma. These shocks can be preceded by extended waves and suprathermal ion foreshocks. Shocks characteristics as well as the level of wave activity near them change as they propagate through the heliosphere and this can impact particle acceleration, and modify the ambient solar wind. In this work we study IP shock evolution and the wave modes upstream of them using a multispacecraft approach with data of Solar Orbiter, STEREO, Parker Solar Probe and Wind. We find that upstream regions can be permeated by whistler waves (f ~ 1 Hz) and/or ultra low frequency (ULF) right-handed waves (f~10-2–10-1 Hz). While whistlers appear to be generated at the shock, the origin of ULF waves is most probably associated with local kinetic ion instabilities. In contrast with planetary bow shocks, most IP shocks have a small Mach number (<4) and most of the upstream waves studied here are mainly transverse and steepening rarely occurs.
How to cite: Blanco-Cano, X., Trotta, D., Hietala, H., Kajdic, P., Rojas-Castillo, D., Dimmock, A., Horbury, T., Vainio, R., and Jian, L.: Waves upstream of interplanetary shocks, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9785, https://doi.org/10.5194/egusphere-egu23-9785, 2023.
