Wave vector analysis methods using multi-point measurements

Narita, Yasuhito; Glaßmeier, K. H.; Motschmann, U.

doi:10.5194/npg-17-383-2010

Cited by 16 publications

(20 citation statements)

References 45 publications

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“…The MSR technique [Narita et al, 2010b[Narita et al, , 2011] is a multispacecraft measurement technique developed for the Cluster mission which is based on the k-filtering/wave telescope techniques [Pinçon and Lefeuvre, 1991;Motschmann et al, 1996] and retains the same advantages of those techniques in that they do not require the 10.1002/2016JA023552 assumption of Taylor's hypothesis [Taylor, 1938]. These techniques are able to estimate the three-dimensional power in wave vector space and can determine the most energetic wave number at each spacecraft frame frequency.…”

Section: Applicability Of the Msr To A Scalar Fieldmentioning

confidence: 99%

“…To investigate the turbulence, we will use the multipoint signal resonator (MSR) technique [Narita et al, 2010b[Narita et al, , 2011 a multispacecraft technique. This technique is derived from the k-filtering/wave telescope techniques [Pinçon and Lefeuvre, 1991;Motschmann et al, 1996;Narita et al, 2010a;Roberts et al, 2014], where the signal-to-noise ratio of the solution is improved.…”

Section: Introductionmentioning

confidence: 99%

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Multipoint analysis of compressive fluctuations in the fast and slow solar wind

Roberts,

Narita,

et al. 2017

JGR Space Physics

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Compressible turbulence in the solar wind is a topic of much recent debate. To understand the various compressive fluctuations at scales comparable to proton characteristic lengths, we use multipoint magnetic field and density data (derived from spacecraft potential which allows higher time resolution than is typically possible than with particle instruments) from the Cluster spacecraft when they were in undisturbed intervals of slow and fast solar wind. The application of the multipoint signal resonator technique is performed for the first time, to the analysis of scalar time series. Fluctuations in the measurements of electron density and in magnitude of the magnetic field (used as a proxy for compressible magnetic fluctuations) are used as inputs in addition to the traditional vector components of the magnetic field. This analysis is performed on two streams of solar wind, one which can be classed as a slow stream and one which can be classed as a fast stream to investigate the difference in the compressible components in the two types of wind. The recovered plasma frame frequencies for the incompressible component show low propagation speed in the plasma frame consistent with previous applications of the method, while the compressible components are more scattered, some with very high phase speeds. Based on these results, we propose a picture of compressive solar wind turbulence as a mixed state of (1) linear modes such as kinetic Alfvén, kinetic slow, and ion Bernstein modes; (2) coherent structures with very small intrinsic frequencies; and (3) nonlinear or sideband modes.

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Section: Applicability Of the Msr To A Scalar Fieldmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Multipoint analysis of compressive fluctuations in the fast and slow solar wind

Roberts,

Narita,

et al. 2017

JGR Space Physics

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“…If the signal comes from a single source (e.g., a localized reconnection event like a single pebble dropped in a pond), it is likely that there will be a unique k for each ω component observed at the spacecraft. For example, the assumption that k = k ( ω ) was used in equation (35) and Figure 8 of Narita et al [].…”

Section: Requirement That There Be a Unique Wave Vector For Each Freqmentioning

confidence: 99%

“…Closely associated with this issue has been the space-time ambiguity where it is unclear whether a temporal fluctuation measured in the spacecraft frame results from a temporal fluctuation in the plasma frame or instead from the spacecraft flying through a spatially dependent structure that is stationary in the plasma frame. The most widely used previous methods to determine the direction and magnitude of k are the minimum-variance method, the phase-difference determination, and the multispacecraft k-filtering method [Sonnerup and Scheible, 1998;Motschmann and Glassmeier, 1998;Balikhin et al, 2003;Narita et al, 2010]. However, some of these methods only resolve the direction relative to the background magnetic field within a sign ambiguity along the field, while others require a wave dispersion relation from a model to resolve the wave vector k. Bellan [2012] proposed that if the wave electric current density J has zero divergence as is true for low-frequency waves such as Alfvén or ion-cyclotron waves, then knowledge of J could provide a means for resolving both k and the space-time ambiguity inherent in single-spacecraft measurements.…”

Section: Introductionmentioning

confidence: 99%

Revised single‐spacecraft method for determining wave vector k and resolving space‐time ambiguity

Bellan

2016

JGR Space Physics

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A practical method is proposed for determining the wave vector of waves from single‐spacecraft measurements. This wave vector knowledge can then be used to remove the space‐time ambiguity produced by frequency Doppler shift associated with spacecraft motion. The method involves applying the Wiener‐Khinchin theorem to cross correlations of the current and magnetic field oscillations and to autocorrelations of the magnetic field oscillations. The method requires that each wave frequency component map to a unique wave vector, a condition presumed true in many spacecraft measurement situations. Examples validating the method are presented.

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“…The Cluster mission [ Escoubet et al , 2001] is suitable for such a task, since its four‐point measurements allow us to determine dispersion relations in three‐dimensional space experimentally. We use the high‐resolution wave‐vector analysis method called the MSR technique (Multi‐point Signal Resonator) [ Narita et al , 2010], and look for dispersion relations in solar wind turbulence at three distinct spatial scales using Cluster: 10,000, 1000, and 100 km.…”

Section: Introductionmentioning

confidence: 99%

Dispersion relation analysis of solar wind turbulence

Narita

Gary

Saito

et al. 2011

Geophys. Res. Lett.

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107

106

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[1] Frequency versus wave number diagram of turbulent magnetic fluctuations in the solar wind was determined for the first time in the wide range over three decades using four Cluster spacecraft. Almost all of the identified waves propagate quasi-perpendicular to the mean magnetic field at various phase speeds, accompanied by a transition from the dominance of outward propagation from the Sun at longer wavelengths into mixture of counter-propagation at shorter wavelengths. Frequency-wave number diagram exhibits largely scattered populations with only weak agreement with magnetosonic and whistler waves. Clear identification of a specific normal mode is difficult, suggesting that nonlinear energy cascade is operating even on small-scale fluctuations.

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Wave vector analysis methods using multi-point measurements

Cited by 16 publications

References 45 publications

Multipoint analysis of compressive fluctuations in the fast and slow solar wind

Multipoint analysis of compressive fluctuations in the fast and slow solar wind

Revised single‐spacecraft method for determining wave vector k and resolving space‐time ambiguity

Dispersion relation analysis of solar wind turbulence

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