POWER ANISOTROPY IN THE MAGNETIC FIELD POWER SPECTRAL TENSOR OF SOLAR WIND TURBULENCE

@article{Wicks2012POWERAI,
  title={POWER ANISOTROPY IN THE MAGNETIC FIELD POWER SPECTRAL TENSOR OF SOLAR WIND TURBULENCE},
  author={Robert T. Wicks and Miriam A. Forman and Timothy S. Horbury and Sean Oughton},
  journal={The Astrophysical Journal},
  year={2012},
  volume={746}
}
We observe the anisotropy of the power spectral tensor of magnetic field fluctuations in the fast solar wind for the first time. In heliocentric RTN coordinates, the power in each element of the tensor has a unique dependence on the angle between the magnetic field and velocity of the solar wind (θB) and the angle of the vector in the plane perpendicular to the velocity (ϕB). We derive the geometrical effect of the high speed flow of the solar wind past the spacecraft on the power spectrum in… 

Figures and Tables from this paper

Direct Measurement of Anisotropic and Asymmetric Wave Vector Spectrum in Ion-scale Solar Wind Turbulence

This analysis represents the first time that a simultaneous measurement of parallel and perpendicular spectral indices at both inertial and kinetic scales has been made directly in wave vector space,

Anisotropies of the Magnetic Field Fluctuations at Kinetic Scales in the Solar Wind: Cluster Observations

We present the first statistical study of the anisotropy of the magnetic field turbulence in the solar wind between 1 and 200 Hz, i.e., from proton to sub-electron scales. We consider 93 ten-minute

IMPRINTS OF EXPANSION ON THE LOCAL ANISOTROPY OF SOLAR WIND TURBULENCE

We study the anisotropy of II-order structure functions (SFs) defined in a frame attached to the local mean field in three-dimensional (3D) direct numerical simulations of magnetohydrodynamic

Anisotropy in solar wind plasma turbulence

TLDR
Evidence for and against wave interpretations and turbulence interpretations of these features will be discussed, and new simulation results concerning evolution of variance anisotropy for different classes of initial conditions, each with typical background solar wind parameters are presented.

CORRELATIONS AT LARGE SCALES AND THE ONSET OF TURBULENCE IN THE FAST SOLAR WIND

We show that the scaling of structure functions of magnetic and velocity fields in a mostly highly Alfvénic fast solar wind stream depends strongly on the joint distribution of the dimensionless

REPRODUCTION OF THE OBSERVED TWO-COMPONENT MAGNETIC HELICITY IN SOLAR WIND TURBULENCE BY A SUPERPOSITION OF PARALLEL AND OBLIQUE ALFVÉN WAVES

The angular distribution of the normalized reduced magnetic helicity density (σrm) in solar wind turbulence reveals two components of distinct polarity in different angle ranges. This kind of

RECONSTRUCTION OF A BROADBAND SPECTRUM OF ALFVÉNIC FLUCTUATIONS

Alfvénic fluctuations in the solar wind exhibit a high degree of velocities and magnetic field correlations consistent with Alfvén waves propagating away and toward the Sun. Two remarkable properties

Parallel-propagating Fluctuations at Proton-kinetic Scales in the Solar Wind Are Dominated By Kinetic Instabilities

We use magnetic helicity to characterize solar wind fluctuations at proton-kinetic scales from Wind observations. For the first time, we separate the contributions to helicity from fluctuations

Turbulence in the solar wind

The solar wind provides a unique natural "laboratory" in which plasma turbulence may be investigated in-situ. Turbulence is statistically reproducible. Thus, in this thesis we investigate plasma

The Role of Proton-Cyclotron Resonance as a Dissipation Mechanism in Solar Wind Turbulence: A Statistical Study at Ion-Kinetic Scales.

We use magnetic field and ion moment data from the MFI and SWE instruments on board the Wind spacecraft to study the nature of solar wind turbulence at ion-kinetic scales. We analyze the spectral

References

SHOWING 1-10 OF 44 REFERENCES

OBSERVATIONS OF ANISOTROPIC SCALING OF SOLAR WIND TURBULENCE

Using high-speed solar wind data recorded by the Ulysses spacecraft, we investigate and estimate the anisotropic inertial range scaling of the interplanetary magnetic field. We apply the method of

DEPENDENCE OF SOLAR-WIND POWER SPECTRA ON THE DIRECTION OF THE LOCAL MEAN MAGNETIC FIELD

Wavelet analysis can be used to measure the power spectrum of solar-wind fluctuations along a line in any direction (θ, ϕ) with respect to the local mean magnetic field B0. This technique is applied

Anisotropic scaling of magnetohydrodynamic turbulence.

TLDR
A quantitative estimate of the anisotropic power and scaling of magnetic field fluctuations in inertial range magnetohydrodynamic turbulence, using a novel wavelet technique applied to spacecraft measurements in the solar wind, shows for the first time that the spacecraft-frame spectrum has a spectral index near 2.

MAGNETIC HELICITY SPECTRUM OF SOLAR WIND FLUCTUATIONS AS A FUNCTION OF THE ANGLE WITH RESPECT TO THE LOCAL MEAN MAGNETIC FIELD

Magnetic field data acquired by the Ulysses spacecraft in high-speed streams over the poles of the Sun are used to investigate the normalized magnetic helicity spectrum σm as a function of the angle

Spacecraft observations of solar wind turbulence: an overview

Spacecraft measurements in the solar wind offer the opportunity to study magnetohydrodynamic (MHD) turbulence in a collisionless plasma in great detail. We review some of the key results of the study

Wave-vector dependence of magnetic-turbulence spectra in the solar wind.

TLDR
From the three-dimensional energy distribution wave vector anisotropy is estimated with respect to directions parallel and perpendicular to the mean magnetic field, and the result suggests the dominance of quasi-two-dimensional turbulence toward smaller spatial scales.

DETAILED FIT OF “CRITICAL BALANCE” THEORY TO SOLAR WIND TURBULENCE MEASUREMENTS

We derive the reduced spectrum of turbulent magnetic fluctuations at different frequencies f which would be observed by a single spacecraft in the solar wind when the magnetic field was at an angle

POSSIBLE EVIDENCE OF ALFVÉN-CYCLOTRON WAVES IN THE ANGLE DISTRIBUTION OF MAGNETIC HELICITY OF SOLAR WIND TURBULENCE

The fluctuating magnetic helicity is considered an important parameter in diagnosing the characteristic modes of solar wind turbulence. Among them is the Alfvén-cyclotron wave, which is probably

Nonaxisymmetric anisotropy of solar wind turbulence.

TLDR
Nonaxisymmetry across the inertial and dissipation ranges is quantified using in situ observations from Cluster and may simply arise as a sampling effect related to Taylor's hypothesis and is not related to the plasma dynamics itself.

Multispacecraft Measurement of Anisotropic Correlation Functions in Solar Wind Turbulence

Multispacecraft measurements in the solar wind are used to determine the field-aligned anisotropy of magnetohydrodynamic inertial range turbulence. The ratio of the parallel to perpendicular