Whistler waves observed by Solar Orbiter/RPW between 0.5 AU and 1 AU

Kretzschmar, M.; Chust, T.; Krasnoselskikh, V.; Graham, Daniel B.; Colomban, Lucas; Maksimović, Milan; Khotyaintsev, Yuri V.; Souček, J.; Steinvall, Konrad; Santolı́k, O.; Jannet, G.; Brochot, J.-Y.; Contel, O. Le; Vecchio, A.; Bonnin, X.; Bale, S. D.; Froment, C.; Larosa, A.; Bergerard-Timofeeva, M.; Fergeau, P.; Lorfèvre, E.; Plettemeier, Dirk; Steller, M.; Štverák, S.; Trávníček, Pavel; Vaivads, A.; Horbury, T. S.; O’Brien, H.; Evans, V.; Angelini, V.; Owen, C. J.

doi:10.1051/0004-6361/202140945

Cited by 27 publications

(28 citation statements)

References 31 publications

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“…This finding is consistent with the observed lack of fast-magnetosonic/whistler waves in Parker Solar Probe data at heliocentric distances 0.13 au (Cattell et al, 2022). Moreover, the majority of the fast-magnetosonic/whistler waves observed farther away from the Sun have a quasi-parallel direction of propagation with respect to the magnetic field (Kretzschmar et al, 2021). Therefore, other mechanisms than the self-induced scattering of strahl electrons by the oblique fast-magnetosonic/whistler instability may thus be needed to explain the observed scattering of strahl electrons into the halo population (e.g., the interaction with pre-existing fastmagnetosonic/whistler waves; Vocks et al, 2005;Vocks and Mann, 2009;Pierrard et al, 2011;Jagarlamudi et al, 2021;Cattell and Vo, 2021;.…”

Section: Electron-driven Instabilitiessupporting

confidence: 89%

Electron-driven instabilities in the solar wind

Verscharen¹,

Chandran²,

Boella³

et al. 2022

Preprint

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The electrons are an essential particle species in the solar wind. They often exhibit nonequilibrium features in their velocity distribution function. These include temperature anisotropies, tails (kurtosis), and reflectional asymmetries (skewness), which contribute a significant heat flux to the solar wind. If these non-equilibrium features are sufficiently strong, they drive kinetic micro-instabilities. We develop a semi-graphical framework based on the equations of quasi-linear theory to describe electron-driven instabilities in the solar wind. We apply our framework to resonant instabilities driven by temperature anisotropies. These include the electron whistler anisotropy instability and the propagating electron firehose instability. We then describe resonant instabilities driven by reflectional asymmetries in the electron distribution function. These include the electron/ion-acoustic, kinetic Alfv én heat-flux, Langmuir, electron-beam, electron/ion-cyclotron, 1

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Section: Electron-driven Instabilitiessupporting

confidence: 89%

Electron-driven instabilities in the solar wind

Verscharen¹,

Chandran²,

Boella³

et al. 2022

Preprint

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“…This finding is consistent with the observed lack of fastmagnetosonic/whistler waves in Parker Solar Probe data at heliocentric distances ≲ 0.13 au (Cattell et al, 2022). Moreover, the majority of the fast-magnetosonic/whistler waves observed farther away from the Sun have a quasiparallel direction of propagation with respect to the magnetic field (Kretzschmar et al, 2021). Therefore, other mechanisms than the self-induced scattering of strahl electrons by the oblique fast-magnetosonic/whistler instability may thus be needed to explain the observed scattering of strahl electrons into the halo population (e.g., the interaction with pre-existing fast-magnetosonic/whistler waves; Vocks et al, 2005;Vocks and Mann, 2009;Pierrard et al, 2011;Jagarlamudi et al, 2021;Cattell and Vo, 2021;.…”

Section: Oblique Fast-magnetosonic/whistler Instabilitysupporting

confidence: 88%

Electron-Driven Instabilities in the Solar Wind

Verscharen

Chandran²,

Boella³

et al. 2022

Front. Astron. Space Sci.

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The electrons are an essential particle species in the solar wind. They often exhibit non-equilibrium features in their velocity distribution function. These include temperature anisotropies, tails (kurtosis), and reflectional asymmetries (skewness), which contribute a significant heat flux to the solar wind. If these non-equilibrium features are sufficiently strong, they drive kinetic micro-instabilities. We develop a semi-graphical framework based on the equations of quasi-linear theory to describe electron-driven instabilities in the solar wind. We apply our framework to resonant instabilities driven by temperature anisotropies. These include the electron whistler anisotropy instability and the propagating electron firehose instability. We then describe resonant instabilities driven by reflectional asymmetries in the electron distribution function. These include the electron/ion-acoustic, kinetic Alfvén heat-flux, Langmuir, electron-beam, electron/ion-cyclotron, electron/electron-acoustic, whistler heat-flux, oblique fast-magnetosonic/whistler, lower-hybrid fan, and electron-deficit whistler instability. We briefly comment on non-resonant instabilities driven by electron temperature anisotropies such as the mirror-mode and the non-propagating firehose instability. We conclude our review with a list of open research topics in the field of electron-driven instabilities in the solar wind.

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“…where V 23 and V 12 are the potential differences between probes 2 and 3 and 1 and 2, respectively, and L y = 6.99 m and L z = 6.97 m are the effective lengths in the y-and z-directions used in this paper. These effective lengths are based on the geometric lengths of the antennas and are in good agreement with estimates of the effective lengths based on deHoffman-Teller analysis using the DC electric and magnetic fields and comparing with the solar wind velocity (Steinvall et al 2021), along with a comparison of the electric and magnetic fields associated with whistler waves (Kretzschmar et al 2021). We apply this same calibration to both LFR and TDS potential data.…”

Section: Instruments and Datasupporting

confidence: 70%

Kinetic electrostatic waves and their association with current structures in the solar wind

Graham¹,

Khotyaintsev²,

Vaivads³

et al. 2021

A&A

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Context. A variety of kinetic electrostatic and electromagnetic waves develop in the solar wind and the relationship between these waves and larger scale structures, such as current sheets and ongoing turbulence, remain a topic of investigation. Similarly, the instabilities producing ion-acoustic waves in the solar wind are still an open question. Aims. The goals of this paper are to investigate electrostatic Langmuir and ion-acoustic waves in the solar wind at 0.5 AU and determine whether current sheets and associated streaming instabilities can produce the observed waves. The relationship between these waves and currents observed in the solar wind is investigated statistically. Methods. Solar Orbiter’s Radio and Plasma Waves instrument suite provides high-resolution snapshots of the fluctuating electric field. The Low Frequency Receiver resolves the waveforms of ion-acoustic waves and the Time Domain Sampler resolves the waveforms of both ion-acoustic and Langmuir waves. Using these waveform data, we determine when these waves are observed in relation to current structures in the solar wind, estimated from the background magnetic field. Results. Langmuir and ion-acoustic waves are frequently observed in the solar wind. Ion-acoustic waves are observed about 1% of the time at 0.5 AU. The waves are more likely to be observed in regions of enhanced currents. However, the waves typically do not occur at current structures themselves. The observed currents in the solar wind are too small to drive instability by the relative drift between single ion and electron populations. When multi-component ion or electron distributions are present, the observed currents may be sufficient for instabilities to occur. Ion beams are the most plausible source of ion-acoustic waves in the solar wind. The spacecraft potential is confirmed to be a reliable probe of the background electron density when comparing the peak frequencies of Langmuir waves with the plasma frequency calculated from the spacecraft potential.

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Whistler waves observed by Solar Orbiter/RPW between 0.5 AU and 1 AU

Cited by 27 publications

References 31 publications

Electron-driven instabilities in the solar wind

Electron-driven instabilities in the solar wind

Electron-Driven Instabilities in the Solar Wind

Kinetic electrostatic waves and their association with current structures in the solar wind

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