EGU22-3195
https://doi.org/10.5194/egusphere-egu22-3195
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

The emission of near-fce harmonic waves at small radial distances from the Sun

Sabrina F. Tigik1, Andris Vaivads1, and David M. Malaspina2,3
Sabrina F. Tigik et al.
  • 1Electrical Engineering / Space Plasma Physics division, School of Electrical Engineering and Computer Science (EECS), KTH Royal Institute of Technology, Sweden (tfsa@kth.se)
  • 2Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, USA
  • 3Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO, USA

Near-fce harmonic waves are prevalent in the high-frequency electric field spectrum during Parker Solar Probe's (PSP) close encounters with the Sun. These waves are electrostatic and tend to occur in regions of a relatively stable magnetic field with low broadband magnetic fluctuation levels. We show that the emissions of near-fce harmonic waves are strongly connected to the magnetic field direction. We express the magnetic field direction in terms of spherical angles, where θB is the elevation angle and φB is the azimuthal angle. Then, we show that near-fce harmonics emissions occur when the magnetic field points in a narrow angular range, bounded by 80° ≤ θB ≤ 100° and 10° ≤ φB ≤ 30°, in most of the cases. We also show that the influence of magnetic field direction on near-fce harmonic waves goes down to the shortest time scales the FIELDS instrument can access. These results suggest that cross-scale interaction might play an essential role in the dynamics of the near-fce harmonics measured by PSP at small radial distances from the Sun. It may also provide important clues about the origin of these waves and their role at the early stages of solar wind evolution.

How to cite: F. Tigik, S., Vaivads, A., and M. Malaspina, D.: The emission of near-fce harmonic waves at small radial distances from the Sun, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3195, https://doi.org/10.5194/egusphere-egu22-3195, 2022.