Tearing Instability and Periodic Density Perturbations in the Slow Solar Wind

Réville, Victor; Velli, Marco; Rouillard, A. P.; Lavraud, B.; Tenerani, Anna; Shi, Chen; Strugarek, Antoine

doi:10.3847/2041-8213/ab911d

Cited by 55 publications

(63 citation statements)

References 41 publications

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“…Therefore, this process may play a role but cannot be dominating the energy input overall. Another likely contribution to the generation of the streamer belt wind is reconnection in the near-Sun HCS (Lavraud et al 2020) triggered by a tearing mode (Réville et al 2020b). The chain of processes involved in the acceleration of the streamer belt wind, however, remains an open question.…”

Section: Discussionmentioning

confidence: 99%

The near-Sun streamer belt solar wind: turbulence and solar wind acceleration

Chen

Chandran

Woodham

et al. 2021

A&A

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The fourth orbit of Parker Solar Probe (PSP) reached heliocentric distances down to 27.9 R , allowing solar wind turbulence and acceleration mechanisms to be studied in situ closer to the Sun than previously possible. The turbulence properties were found to be significantly different in the inbound and outbound portions of PSP's fourth solar encounter, which was likely due to the proximity to the heliospheric current sheet (HCS) in the outbound period. Near the HCS, in the streamer belt wind, the turbulence was found to have lower amplitudes, higher magnetic compressibility, a steeper magnetic field spectrum (with a spectral index close to -5/3 rather than -3/2), a lower Alfvénicity, and a '1/ f ' break at much lower frequencies. These are also features of slow wind at 1 au, suggesting the near-Sun streamer belt wind to be the prototypical slow solar wind. The transition in properties occurs at a predicted angular distance of ≈ 4 • from the HCS, suggesting ≈ 8 • as the full-width of the streamer belt wind at these distances. While the majority of the Alfvénic turbulence energy fluxes measured by PSP are consistent with those required for reflection-driven turbulence models of solar wind acceleration, the fluxes in the streamer belt are significantly lower than the model predictions, suggesting that additional mechanisms are necessary to explain the acceleration of the streamer belt solar wind.

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Section: Discussionmentioning

confidence: 99%

The near-Sun streamer belt solar wind: turbulence and solar wind acceleration

Chen

Chandran

Woodham

et al. 2021

A&A

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“…Recent work by Réville et al. (2020) demonstrated that PDSs associated with helmet streamers could be the result of the tearing mode instability at the base of the heliospheric current sheet. They argue that the larger, ∼10–20 hr periodicities, as well as the ∼1–2 hr periodicities that are observed, are all the result of the tearing mode.…”

Section: Discussionmentioning

confidence: 99%

Inherent Length Scales of Periodic Mesoscale Density Structures in the Solar Wind Over Two Solar Cycles

2020

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It is now well established through multiple event and statistical studies that the solar wind at 1 AU contains contains periodic, mesoscale (L ∼ 100–1,000 Mm) structures in the proton density. Composition variations observed within these structures and remote sensing observations of similar structures in the young solar wind indicate that at least some of these periodic structures originate in the solar atmosphere as a part of solar wind formation. Viall et al. (2008, https://doi.org/10.1029/2007JA012881) analyzed 11 years of data from the Wind spacecraft near L1 and demonstrated a recurrence to the observed length scales of periodic structures in the solar wind proton density. In the time since that study, Wind has collected 14 additional years of solar wind data, new moment analysis of the Wind SWE data is available, and new methods for spectral background approximation have been developed. In this study, we analyze 25 years of Wind data collected near L1 and produce occurrence distributions of statistically significant periodic length scales in proton density. The results significantly expand upon the Viall et al. (2008, https://doi.org/10.1029/2007JA012881) study and further show a possible relation of the length scales to solar “termination” events.

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“…Several studies also found composition signatures, which could only have come from formation at the Sun . Recent work by Réville et al (2020) demonstrated that PDSs associated with helmet streamers could be the result of the tearing mode instability at the base of the heliospheric current sheet. They argue that the larger, ∼10-20 hr periodicities, as well as the ∼1-2 hr periodicities that are observed, are all the result of the tearing mode.…”

Section: Journal Of Geophysical Research: Space Physicsmentioning

confidence: 99%

Inherent length scales of periodic mesoscale density structures in the solar wind over two solar cycles

Kepko

Viall²,

Wolfinger

2020

Preprint

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It is now well established through multiple event and statistical studies that the solar wind at 1 AU contains contains periodic, mesoscale (L ∼ 100-1,000 Mm) structures in the proton density. Composition variations observed within these structures and remote sensing observations of similar structures in the young solar wind indicate that at least some of these periodic structures originate in the solar atmosphere as a part of solar wind formation. Viall et al. (2008, https://doi.org/10.1029/2007JA012881) analyzed 11 years of data from the Wind spacecraft near L1 and demonstrated a recurrence to the observed length scales of periodic structures in the solar wind proton density. In the time since that study, Wind has collected 14 additional years of solar wind data, new moment analysis of the Wind SWE data is available, and new methods for spectral background approximation have been developed. In this study, we analyze 25 years of Wind data collected near L1 and produce occurrence distributions of statistically significant periodic length scales in proton density. The results significantly expand upon the Viall et al. (2008, https://doi.org/ 10.1029/2007JA012881) study and further show a possible relation of the length scales to solar "termination" events. Plain Language SummaryThe plasma and magnetic field in the solar atmosphere flows away from the Sun, filling interplanetary space. This plasma is called the solar wind, and it constantly bombards all of the planets in the solar system. The solar wind is composed of mesoscale structures-larger than scales where particle dynamics are important, but smaller than global scales-of increased density, and therefore pressure. A subgroup of mesoscale density structures is of order the size of Earth's magnetosphere, and often quasi-periodic. These periodic density structures are an important driver of dynamics in Earth's space environment. In this study, we examine the statistics of the size scales of these structures using 25 years, or approximately two solar cycles, of solar wind data measured by the Wind spacecraft. We confirm earlier work showing a persistence of particular length scales of the periodicities and find a possible relation of the length scales to the end of a Hale magnetic cycle. In addition to their driving of magnetospheric dynamics, periodic density structures are a tracer of solar wind formation. Their lengths scales and evolution are an important constraint of solar wind formation.

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Tearing Instability and Periodic Density Perturbations in the Slow Solar Wind

Cited by 55 publications

References 41 publications

The near-Sun streamer belt solar wind: turbulence and solar wind acceleration

The near-Sun streamer belt solar wind: turbulence and solar wind acceleration

Inherent Length Scales of Periodic Mesoscale Density Structures in the Solar Wind Over Two Solar Cycles

Inherent length scales of periodic mesoscale density structures in the solar wind over two solar cycles

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