Περίληψη:
Context. On December 27, 2020, Solar Orbiter completed its first gravity
assist manoeuvre of Venus (VGAM1). While this flyby was performed to
provide the spacecraft with sufficient velocity to get closer to the Sun
and observe its poles from progressively higher inclinations, the Radio
and Plasma Wave (RPW) consortium, along with other operational in situ
instruments, had the opportunity to perform high cadence measurements
and study the plasma properties in the induced magnetosphere of Venus.
Aims. In this paper, we review the main observations of the RPW
instrument during VGAM1. They include the identification of a number of
magnetospheric plasma wave modes, measurements of the electron number
densities computed using the quasi-thermal noise spectroscopy technique
and inferred from the probe-to-spacecraft potential, the observation of
dust impact signatures, kinetic solitary structures, and localized
structures at the bow shock, in addition to the validation of the wave
normal analysis on-board from the Low Frequency Receiver. Methods. We
used the data products provided by the different subsystems of RPW to
study Venus' induced magnetosphere. Results. The results include the
observations of various electromagnetic and electrostatic wave modes in
the induced magnetosphere of Venus: strong emissions of similar to 100
Hz whistler waves are observed in addition to electrostatic ion acoustic
waves, solitary structures and Langmuir waves in the magnetosheath of
Venus. Moreover, based on the different levels of the wave amplitudes
and the large-scale variations of the electron number densities, we
could identify different regions and boundary layers at Venus.
Conclusions. The RPW instrument provided unprecedented AC magnetic and
electric field measurements in Venus' induced magnetosphere for
continuous frequency ranges and with high time resolution. These data
allow for the conclusive identification of various plasma waves at
higher frequencies than previously observed and a detailed investigation
regarding the structure of the induced magnetosphere of Venus.
Furthermore, noting that prior studies were mainly focused on the
magnetosheath region and could only reach 10-12 Venus radii (R-V) down
the tail, the particular orbit geometry of Solar Orbiter's VGAM1,
allowed the first investigation of the nature of the plasma waves
continuously from the bow shock to the magnetosheath, extending to
similar to 70R(V) in the far distant tail region.
Συγγραφείς:
Hadid, L. Z.
Edberg, N. J. T.
Chust, T.
Pisa, D. and
Dimmock, A. P.
Morooka, M. W.
Maksimovic, M.
Khotyaintsev,
V, Yu
Soucek, J.
Kretzschmar, M.
Vecchio, A.
Le Contel,
O.
Retino, A.
Allen, R. C.
Volwerk, M.
Fowler, C. M. and
Sorriso-Valvo, L.
Karlsson, T.
Santolik, O.
Kolmasova, I and
Sahraoui, F.
Stergiopoulou, K.
Moussas, X.
Issautier, K. and
Dewey, R. M.
Wolt, M. Klein
Malandraki, O. E.
Kontar, E. P.
and Howes, G. G.
Bale, S. D.
Horbury, T. S.
Martinovic, M.
and Vaivads, A.
Krasnoselskikh, V
Lorfevre, E.
Plettemeier,
D.
Steller, M.
Stverak, S.
Travnicek, P.
O'Brien, H. and
Evans, V
Angelini, V
Velli, M. C.
Zouganelis, I
