Scale-dependent Polarization of Solar Wind Velocity Fluctuations at the Inertial and Kinetic Scales

Šafránková, Jana; Němeček, Zdenek; Němec, F.; Verscharen, Daniel; Chen, Christopher H. K.; Ďurovcová, Tereza; Рязанцева, М. О.

doi:10.3847/1538-4357/aaf239

Cited by 23 publications

(21 citation statements)

References 44 publications

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“…cross-calibrations with ACE measurements for the OMNI datasets (King & Papitashvili, 2005) or as a source of magnetic-field measurements for spacecraft without a working magnetometer (Pitňa et al, 2019;Šafránková et al, 2019). Leamon et al (1998) attempted to distinguish between wave and turbulence paradigms at the dissipation scale using Wind MFI solar wind data.…”

Section: Reviews Of Geophysicsmentioning

confidence: 99%

A Quarter Century ofWindSpacecraft Discoveries

Wilson

Brosius

Gopalswamy

et al. 2021

Reviews of Geophysics

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Section: Reviews Of Geophysicsmentioning

confidence: 99%

A Quarter Century ofWindSpacecraft Discoveries

Wilson

Brosius

Gopalswamy

et al. 2021

Reviews of Geophysics

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“…Image adapted from [104] and reproduced by permission of the AAS. Although the solar wind is populated predominantly with Alfvénic and slow mode fluctuations [117], the mirror mode (MM) waves are frequently observed in shock sheaths. Due to the quasi-perpendicular shock compression, ions heat preferentially in the perpendicular direction which leads to an increase of temperature anisotropy and the instability threshold (β ⊥ /β − 1 − 1/β ⊥ 0) can be easily reached.…”

Section: Kinetic Rangementioning

confidence: 99%

Turbulence Upstream and Downstream of Interplanetary Shocks

et al. 2021

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The paper reviews the interaction of collisionless interplanetary (IP) shocks with the turbulent solar wind. The coexistence of shocks and turbulence plays an important role in understanding the acceleration of particles via Fermi acceleration mechanisms, the geoeffectiveness of highly disturbed sheaths following IP shocks and, among others, the nature of the fluctuations themselves. Although our knowledge of physics of upstream and downstream shock regions has been greatly improved in recent years, many aspects of the IP-shock/turbulence interaction are still poorly known, for example, the nature of turbulence, its characteristics on spatial and temporal scales, how it decays, its relation to shock passage and others. We discuss properties of fluctuations ahead (upstream) and behind (downstream) of IP shock fronts with the focus on observations. Some of the key characteristics of the upstream/downstream transition are 1) enhancement of the power in the inertial range fluctuations of the velocity, magnetic field and density is roughly one order of magnitude, 2) downstream fluctuations are always more compressible than the upstream fluctuations, and 3) energy in the inertial range fluctuations is kept constant for a significant time after the passage of the shock. In this paper, we emphasize that–for one point measurements–the downstream region should be viewed as an evolutionary record of the IP shock propagation through the plasma. Simultaneous measurements of the recently launched spacecraft probing inner parts of the Solar System will hopefully shed light on some of these questions.

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“…These fluctuations are characterised by self-consistent interactions between the fields and the particles. Therefore, the observation of the fluctuations in the particle VDF will give us insight into the nature of the turbulent fluctuations in general (Šafránková et al 2019;Wu et al 2019). Furthermore, the secular transfer of energy from the turbulent fluctuations into particle heating creates characteristic signatures in the velocity distribution such as the formation of quasi-linear plateaus through cyclotron-resonant and Landauresonant dissipation (Dusenbery & Hollweg 1981;Marsch et al 1982Marsch et al , 2003Isenberg & Hollweg 1983) or flattening of the core of the distribution through stochastic heating (Klein & Chandran 2016).…”

Section: Primary Science Motivationsmentioning

confidence: 99%

The Solar Orbiter Solar Wind Analyser (SWA) suite

Owen

Bruno

Livi

et al. 2020

A&A

194

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The Solar Orbiter mission seeks to make connections between the physical processes occurring at the Sun or in the solar corona and the nature of the solar wind created by those processes which is subsequently observed at the spacecraft. The mission also targets physical processes occurring in the solar wind itself during its journey from its source to the spacecraft. To meet the specific mission science goals, Solar Orbiter will be equipped with both remote-sensing and in-situ instruments which will make unprecedented measurements of the solar atmosphere and the inner heliosphere. A crucial set of measurements will be provided by the Solar Wind Analyser (SWA) suite of instruments. This suite consists of an Electron Analyser System (SWA-EAS), a Proton and Alpha particle Sensor (SWA-PAS), and a Heavy Ion Sensor (SWA-HIS) which are jointly served by a central control and data processing unit (SWA-DPU). Together these sensors will measure and categorise the vast majority of thermal and suprathermal ions and electrons in the solar wind and determine the abundances and charge states of the heavy ion populations. The three sensors in the SWA suite are each based on the top hat electrostatic analyser concept, which has been deployed on numerous space plasma missions. The SWA-EAS uses two such heads, each of which have 360° azimuth acceptance angles and ±45° aperture deflection plates. Together these two sensors, which are mounted on the end of the boom, will cover a full sky field-of-view (FoV) (except for blockages by the spacecraft and its appendages) and measure the full 3D velocity distribution function (VDF) of solar wind electrons in the energy range of a few eV to ∼5 keV. The SWA-PAS instrument also uses an electrostatic analyser with a more confined FoV (−24° to +42° × ±22.5° around the expected solar wind arrival direction), which nevertheless is capable of measuring the full 3D VDF of the protons and alpha particles arriving at the instrument in the energy range from 200 eV/q to 20 keV/e. Finally, SWA-HIS measures the composition and 3D VDFs of heavy ions in the bulk solar wind as well as those of the major constituents in the suprathermal energy range and those of pick-up ions. The sensor resolves the full 3D VDFs of the prominent heavy ions at a resolution of 5 min in normal mode and 30 s in burst mode. Additionally, SWA-HIS measures 3D VDFs of alpha particles at a 4 s resolution in burst mode. Measurements are over a FoV of −33° to +66° × ±20° around the expected solar wind arrival direction and at energies up to 80 keV/e. The mass resolution (m/Δm) is > 5. This paper describes how the three SWA scientific sensors, as delivered to the spacecraft, meet or exceed the performance requirements originally set out to achieve the mission’s science goals. We describe the motivation and specific requirements for each of the three sensors within the SWA suite, their expected science results, their main characteristics, and their operation through the central SWA-DPU. We describe the combined data products that we expect to return from the suite and provide to the Solar Orbiter Archive for use in scientific analyses by members of the wider solar and heliospheric communities. These unique data products will help reveal the nature of the solar wind as a function of both heliocentric distance and solar latitude. Indeed, SWA-HIS measurements of solar wind composition will be the first such measurements made in the inner heliosphere. The SWA data are crucial to efforts to link the in situ measurements of the solar wind made at the spacecraft with remote observations of candidate source regions. This is a novel aspect of the mission which will lead to significant advances in our understanding of the mechanisms accelerating and heating the solar wind, driving eruptions and other transient phenomena on the Sun, and controlling the injection, acceleration, and transport of the energetic particles in the heliosphere.

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Scale-dependent Polarization of Solar Wind Velocity Fluctuations at the Inertial and Kinetic Scales

Cited by 23 publications

References 44 publications

A Quarter Century ofWindSpacecraft Discoveries

A Quarter Century ofWindSpacecraft Discoveries

Turbulence Upstream and Downstream of Interplanetary Shocks

The Solar Orbiter Solar Wind Analyser (SWA) suite

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