Turbulence associated with corotating interaction regions at 1AU: Inertial range cross-helicity spectra

Smith, Charles W.; Tessein, Jeffrey A.; Vasquez, Bernard J.; Skoug, R. M.

doi:10.1029/2011ja016645

Cited by 16 publications

(24 citation statements)

References 38 publications

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“…Grappin et al [1990] found that particularly inward fluctuations are enhanced by compression, while Bruno and Bavassano [1993] found density and magnetic field fluctuations to destroy the correlation between the velocity and magnetic field. Also, velocity shear in the stream interaction region can transfer energy to the fluctuations creating large amplitude inward and outward fluctuations [Coleman Jr., 1968;Smith et al, 2011]. All these are consistent with the high B Z we observe for low Alfvénicity in the leading part.…”

Section: Alfvénicity In the Solar Windsupporting

confidence: 87%

An automated identification method for Alfvénic streams and their geoeffectiveness

2013

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[1] Previous statistical studies have found a close relationship between high-speed streams and high-latitude geomagnetic activity. The speed by itself would increase the geoeffectivity of the solar wind. But it is also believed that pure Alfvénic fluctuations, often found in the trailing part of the streams, play a role in the solar wind driving of geomagnetic activity by amplifying the north-south component of the magnetic field (B Z ), and thereby the dayside reconnection electric field. By automatically identifying slow and fast solar wind streams and by analyzing them for more than one solar cycle, we aimed to study the relation between speed, Alfvénicity, and B Z in the solar wind. It was found out that streams, whose trailing parts are dominated by pure Alfvénic fluctuations, are the most geoeffective streams on average. However, it is not the pure Alfvénic fluctuations themselves which cause the streams to be more geoeffective. There is only a variation of about 10% in B Z due to the Alfvénicity of the fluctuations. Instead the streams are more geoeffective because the pure Alfvénic fluctuations tend to occur during high-solar wind speed and strong interplanetary magnetic field. There is a substantial variation within the solar cycle of how Alfvénic the solar-wind streams are, and years with many extremely Alfvénic streams tend to have more days with moderately large geoeffectivity. The list of solar wind streams is included as extra material to this paper.

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Section: Alfvénicity In the Solar Windsupporting

confidence: 87%

An automated identification method for Alfvénic streams and their geoeffectiveness

2013

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“… Borovsky and Denton [2010] argue there is no evidence of shear‐induced turbulence. We must disagree with this statement and offer evidence contrary to our companion paper [ Smith et al , 2011]. The analysis of Horbury and Schmidt [1999] also discounts this interpretation.…”

Section: Introductioncontrasting

confidence: 69%

“…Waves upstream of shocks are a good example of the former situation [ Lee , 1983] while the general absence or difficulty in finding waves due to interstellar pickup ions in the outer heliosphere [ Lee and Ip , 1987; Murphy et al , 1995; Isenberg , 1995] is a good example of the latter dynamic. Smith et al [2011] show distinct signatures of energy injection within the cross helicity spectra, but finds no clear evidence for wave injection within the power spectrum.…”

Section: Introductionmentioning

confidence: 89%

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Turbulence associated with corotating interaction regions at 1 AU: Inertial and dissipation range magnetic field spectra

et al. 2011

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[1] We examine five Corotating Interaction Regions (CIRs) observed during the recent solar minimum by the Advanced Composition Explorer spacecraft at 1 AU. We apply a familiar series of spectral examinations and compare quantities such as the variance anisotropy, spectral index, cross-and magnetic helicities, and the infered geometry of the wave vectors against established correlations seen in 1 AU turbulence apart from CIR regions. We find variance anisotropies that scale with plasma beta and spectral amplitude, spectral indices in the same familiar ranges, indices within the dissipation range scaling with the apparent rate of energy cascade within the inertial range, and the same linear relationship between cross-and magnetic helicities. As the results agree with earlier established correlations, we conclude that the rate of energy injection by large-scale shear is sufficiently slow as to allow for significant reorganization of the injected energy by the turbulent cascade. This does not mean that there is no evidence of newly injected energy as a result of that large-scale shear. Our companion paper argues that there is significant energy injection within the CIRs. This analysis only argues that energy injection is too slow to fully dominate the interplanetary spectrum.

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“…This avoids the complications associated with third-moment expressions that are applicable to shear regions [117][118][119]. It also fails to address questions of in situ generation of turbulence in these regions [120][121][122]. As with our earlier papers, we interpolate the results of each 1 h sample onto a common spatial grid that is equivalent to measurements with a 400 km s −1 wind speed.…”

Section: Discussionmentioning

confidence: 99%

Third-moment descriptions of the interplanetary turbulent cascade, intermittency and back transfer

Coburn

Forman

Smith

et al. 2015

Phil. Trans. R. Soc. A.

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One contribution of 11 to a theme issue 'Dissipation and heating in solar wind turbulence' . We review some aspects of solar wind turbulence with an emphasis on the ability of the turbulence to account for the observed heating of the solar wind. Particular attention is paid to the use of structure functions in computing energy cascade rates and their general agreement with the measured thermal proton heating. We then examine the use of 1 h data samples that are comparable in length to the correlation length for the fluctuations to obtain insights into local inertial range dynamics and find evidence for intermittency in the computed energy cascade rates. When the magnetic energy dominates the kinetic energy, there is evidence of anti-correlation in the cascade of energy associated with the outward-and inward-propagating components that we can only partially explain.

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Turbulence associated with corotating interaction regions at 1AU: Inertial range cross-helicity spectra

Cited by 16 publications

References 38 publications

An automated identification method for Alfvénic streams and their geoeffectiveness

An automated identification method for Alfvénic streams and their geoeffectiveness

Turbulence associated with corotating interaction regions at 1 AU: Inertial and dissipation range magnetic field spectra

Third-moment descriptions of the interplanetary turbulent cascade, intermittency and back transfer

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