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Accueil > A propos du LPP > Communication > Actualités archivées > 2022 > Two articles led by LPP are published in Astronomy & Astrophysics special issue dedicated for the first observations of Solar Orbiter

Two articles led by LPP are published in Astronomy & Astrophysics special issue dedicated for the first observations of Solar Orbiter

LPP is directly involved in the ESA/NASA Solar Orbiter mission by delivering the Low Frequency Receiver (LFR, Lead-CoI : Thomas Chust) which is part of the Radio and Plasma Wave (RPW) instrumental consortium led by LESIA (PI : Milan Maksimovic). The spacecraft was launched on the 10th of February 2020 to study the properties and the dynamics of the upper atmosphere of the Sun and the solar wind.

1. Observations of whistler mode waves by Solar Orbiter’s RPW Low Frequency Receiver (LFR) : In-flight performance and first results

The LFR is designed to characterize the low frequency (≤ 10 kHz) electric and magnetic fields that develop, propagate, interact, and dissipate in the solar wind plasma. Combined with observations of the particles and the DC magnetic field, LFR measurements will help to improve the understanding of the heating and acceleration processes at work during solar wind expansion.
In this paper, T. Chust et al. 2021 demonstrate the capability of LFR to observe and analyze a variety of low frequency plasma waves by taking advantage of whistler mode wave observations made just after the near-Earth commissioning phase of Solar Orbiter. In particular, this is related to its capability of measuring the wave normal vector, the phase velocity, and the Poynting vector for determining the propagation characteristics of the waves. Several case studies of whistler mode waves are presented, using all possible LFR onboard digital processing products, waveforms, spectral matrices, and basic wave parameters. Here, whistler mode waves are very properly identified and characterized, along with their Doppler-shifted frequency, based on the waveform capture as well as on the LFR onboard spectral analysis. These first whistler observations show a good overall consistency between the RPW LFR data, indicating that many science results on these waves, as well as on other plasma waves, can be obtained by Solar Orbiter in the solar wind.

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Figure 1
Identification dans le vent solaire d’ondes sur le mode de sifflement se propageant dans le sens anti-solaire en comparant les vitesses de phase observées (lignes oranges ou bleues) avec celles du mode de sifflement théoriques décalées (+k) par effet Doppler (lignes rouges) : (a) à partir des formes d’onde (jeu de données SWF), (b) à partir des produits de données spectrales calculées à bord (jeu de données BP2).

2. Solar Orbiter’s first Venus flyby : observations from the Radio and Plasma Wave instrument

On December 27, 2020, Solar Orbiter completed its first gravity assist manoeuvre of Venus (VGAM1) providing the spacecraft with sufficient velocity to get closer to the Sun and observe its poles from progressively higher inclinations. During this flyby the RPW consortium had the opportunity to perform high cadence measurements and study the plasma properties in the induced magnetosphere of Venus.
In this paper, L. Z. Hadid et al., 2021 review the main observations of the RPW instrument during VGAM1 which provided unprecedented high frequency magnetic and electric field measurements in Venus’ induced magnetosphere for continuous frequency ranges and with high time resolution. These observations allowed conclusive identification of various plasma waves at higher frequencies than previously observed and detailed investigation regarding the structure of the induced magnetosphere of Venus. Furthermore, the particular orbit geometry of Solar Orbiter, allowed the first investigation of the nature of the plasma waves continuously from the bow-shock to the magnetosheath, extending to ∼70 planetary radii in the far distant tail region.

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Figure 2
Les spectres de densité du champ électrique (a) et magnétique (b) calculés en utilisant les données RPW pendant le premier survol de Vénus.

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CNRS Ecole Polytechnique Sorbonne Université Université Paris-Saclay Observatoire de Paris
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Exploitant du site : Laboratoire de Physique des Plasmas, Ecole Polytechnique route de Saclay F-91128 PALAISEAU CEDEX
Hébergeur : Laboratoire de Physique des Plasmas, Ecole Polytechnique route de Saclay F-91128 PALAISEAU CEDEX
Directeur de la publication : Dominique Fontaine (Directrice)