Intermittency and Local Heating in the Solar Wind

Osman, K. T.; Matthaeus, W. H.; Wan, Minping; Rappazzo, A. F.

doi:10.1103/physrevlett.108.261102

Cited by 141 publications

(187 citation statements)

References 33 publications

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“…Furthermore, it is shown directly that the ion energization resulting from the Landau damping of turbulent electromagnetic fluctuations is spatially non-uniform, in contrast to naive expectations that Landau damping leads to spatially uniform energization, likely arising from the plane wave decomposition typically used to derive linear Landau damping. Further work using field-particle correlations will address whether Landau damping can effectively lead to the spatially intermittent plasma heating in the vicinity of current sheets found in plasma turbulence simulations Karimabadi et al 2013;Wu et al 2013;Zhdankin et al 2013) and inferred from solar wind observations (Osman et al , 2012Perri et al 2012;Wang et al 2013;Wu et al 2013;Osman et al 2014a).…”

Section: Discussionmentioning

confidence: 99%

Diagnosing collisionless energy transfer using field–particle correlations: gyrokinetic turbulence

2017

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Determining the physical mechanisms that extract energy from turbulent fluctuations in weakly collisional magnetized plasmas is necessary for a more complete characterization of the behaviour of a variety of space and astrophysical plasmas. Such a determination is complicated by the complex nature of the turbulence as well as observational constraints, chiefly that in situ measurements of such plasmas are typically only available at a single point in space. Recent work has shown that correlations between electric fields and particle velocity distributions constructed from single-point measurements produce a velocity-dependent signature of the collisionless damping mechanism. We extend this work by constructing field-particle correlations using data sets drawn from single points in strongly driven, turbulent, electromagnetic gyrokinetic simulations to demonstrate that this technique can identify the collisionless mechanisms operating in such systems. The velocity-space structure of the correlation between proton distributions and parallel electric fields agrees with expectations of resonant mechanisms transferring energy collisionlessly in turbulent systems. This work motivates the eventual application of field-particle correlations to spacecraft measurements in the solar wind, with the ultimate goal to determine the physical mechanisms that dissipate magnetized plasma turbulence.

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Section: Discussionmentioning

confidence: 99%

Diagnosing collisionless energy transfer using field–particle correlations: gyrokinetic turbulence

2017

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“…Various studies based on numerical simulations [24,25,27,[47][48][49][50] and solar wind data [23,[51][52][53][54] support the idea that enhanced kinetic activity, such as temperature anisotropy, heating, particle acceleration, and departures from Maxwellian velocity distributions in general, all of which commonly observed in astrophysical and laboratory plasmas, are strongly inhomogeneous. These effects are associated typically with coherent structures such as magnetic structures.…”

Section: A Energy Conversion Related To Coherent Structuresmentioning

confidence: 99%

Energy transfer, pressure tensor, and heating of kinetic plasma

et al. 2017

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Kinetic plasma turbulence cascade spans multiple scales ranging from macroscopic fluid flow to sub-electron scales. Mechanisms that dissipate large scale energy, terminate the inertial range cascade and convert kinetic energy into heat are hotly debated. Here we revisit these puzzles using fully kinetic simulation. By performing scale-dependent spatial filtering on the Vlasov equation, we extract information at prescribed scales and introduce several energy transfer functions. This approach allows highly inhomogeneous energy cascade to be quantified as it proceeds down to kinetic scales. The pressure work, − (P · ∇) · u, can trigger a channel of the energy conversion between fluid flow and random motions, which is a collision-free generalization of the viscous dissipation in collisional fluid. Both the energy transfer and the pressure work are strongly correlated with velocity gradients.

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“…This finding was criticized based on an analysis of nearest neighbour temperatures [85]. However, a more complete analysis of the proton temperatures near PVI events indicates that the average temperature falls off gradually as distance from the identified discontinuities increases [86]. There is a characteristic core of elevated temperature that is about 100 000 km wide and a slower fall-off to distances beyond a correlation scale (approx.…”

Section: Evidence For Coherent Structures In the Solar Windmentioning

confidence: 99%