3D turbulent reconnection: Theory, tests, and astrophysical implications

Lazarían, A.; Eyink, Gregory L.; Jafari, Amir; Kowal, Grzegorz; Li, Hui; Xu, Siyao; Vishniac, Ethan T.

doi:10.1063/1.5110603

Cited by 183 publications

(160 citation statements)

References 340 publications

(579 reference statements)

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“…Acceleration mechanisms alternative to DSA have also been proposed and studied (see e.g. Lazarian et al 2020). In this article, however, we focus on DSA, which is still the best studied and the most promising, in this context, to reach the highest energies.…”

Section: Recent Developments On Cr Acceleration In Snrsmentioning

confidence: 99%

On particle acceleration and transport in plasmas in the Galaxy: theory and observations

Amato

Casanova

2021

J. Plasma Phys.

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Accelerated particles are ubiquitous in the Cosmos and play a fundamental role in many processes governing the evolution of the Universe at all scales, from the sub-AU scale relevant for the formation and evolution of stars and planets to the Mpc scale involved in Galaxy assembly. We reveal the presence of energetic particles in many classes of astrophysical sources thanks to their production of non-thermal radiation, and we detect them directly at the Earth as cosmic rays. In the last two decades both direct and indirect observations have provided us a wealth of new, high-quality data about cosmic rays and their interactions both in sources and during propagation, in the Galaxy and in the Solar System. Some of the new data have confirmed existing theories about particle acceleration and propagation and their interplay with the environment in which they occur. Some others have brought about interesting surprises, whose interpretation is not straightforward within the standard framework and may require a change of paradigm in terms of our ideas about the origin of cosmic rays of different species or in different energy ranges. In this article, we focus on cosmic rays of galactic origin, namely with energies below a few petaelectronvolts, where a steepening is observed in the spectrum of energetic particles detected at the Earth. We review the recent observational findings and the current status of the theory about the origin and propagation of galactic cosmic rays.

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Section: Recent Developments On Cr Acceleration In Snrsmentioning

confidence: 99%

On particle acceleration and transport in plasmas in the Galaxy: theory and observations

Amato

Casanova

2021

J. Plasma Phys.

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“…For reconnection layers much wider than the corresponding plasma scales, the magnetohydrodynamic (MHD) approximation is applicable. The 3D simulations in this regime (Kowal et al 2009(Kowal et al , 2017(Kowal et al , 2019Beresnyak 2017) suggest that the fast reconnection is induced by turbulence and the results correspond to turbulent reconnection theory (Lazarian & Vishniac 1999, see also Lazarian et al 2020 for a review), one of the dramatic predictions of which (the violation of the flux freezing in turbulent fluids) has been tested recently (Eyink et al 2013). Nevertheless, the key issue of the trigger of fast reconnection is not settled.…”

Section: Introductionmentioning

confidence: 98%

Onset of Turbulent Fast Magnetic Reconnection Observed in the Solar Atmosphere

Chitta

Lazarían

2020

ApJL

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Fast magnetic reconnection powers explosive events throughout the universe, from gamma-ray bursts to solar flares. Despite its importance, the onset of astrophysical fast reconnection is the subject of intense debate and remains an open question in plasma physics. Here we report high-cadence observations of two reconnection-driven solar microflares obtained by the Interface Region Imaging Spectrograph that show persistent turbulent flows preceding flaring. The speeds of these flows are comparable to the local sound speed initially, suggesting the onset of fast reconnection in a highly turbulent plasma environment. Our results are in close quantitative agreement with the theory of turbulence-driven reconnection as well as with numerical simulations in which fast magnetic reconnection is induced by turbulence.

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“…Magnetic fields in such environments are usually visualized in terms of their field lines, which may undergo a spontaneous process of breaking apart and re-connecting again, which may accelerate the magnetized fluid by means of the Lorentz forces (i.e. magnetic reconnection; for a review see e.g., [10] and [14]). However, as discussed above, the magnetic field lines in such dissipative and dynamic media cannot be described as continuously evolving curves in space.…”

Section: Field Linesmentioning

confidence: 99%

“…As for physical applications, once again, we can think about magnetic fields. Magnetic topology in magnetized fluids is often claimed to change during magnetic reconnection-eruptive fluid motions spontaneously driven by Lorentz forces generated by the relaxing field, see e.g., [14,17]. Magnetic field is governed by the induction equation and the velocity field by Navier-Stokes equation.…”

Section: ( )mentioning

confidence: 99%

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Topological theory of physical fields

Jafari

Vishniac

2020

J. Phys. Commun.

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We study the topology associated with physical vector and scalar fields. A mathematical object, e.g., a ball, can be continuously deformed, without tearing or gluing, to make other topologically equivalent objects, e.g., a cube or a solid disk. If tearing or gluing get involved, i.e. the deformation is not continuous anymore, the initial topology will consequently change giving rise to a topologically distinct object, e.g., a torus. This simple concept in general topology may be employed in the study of physical systems described by fields. Instead of continuously deforming objects, we can take a continuously evolving field, with an appropriately defined topology, such that the topology remains unchanged in time unless the system undergoes an important physical change, e.g., a transition to a different energy state. For instance, a sudden change in the magnetic topology in an energetically relaxing plasma, a process called reconnection, strongly affects the dynamics, e.g., it is involved in launching solar flares and generating large scale magnetic fields in astrophysical objects. In this topological formalism, the magnetic topology in a plasma can spontaneously change due to the presence of dissipative terms in the induction equation which break its time symmetry. We define a topology for the vector field F in the phase space ( ) F x, . As for scalar fields represented by a perfect fluid, e.g., the inhomogeneous inflaton or Higgs fields, the fluid velocity u defines the corresponding topology. The vector field topology in its corresponding phase space ( ) F x, will be preserved in time if certain conditions including time reversal invariance are satisfied by the field and its governing differential equation. Otherwise, the field's topology can suddenly change at some point, similar to a spontaneously broken symmetry, as time advances, e.g., corresponding to an energy transition.

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3D turbulent reconnection: Theory, tests, and astrophysical implications

Cited by 183 publications

References 340 publications

On particle acceleration and transport in plasmas in the Galaxy: theory and observations

On particle acceleration and transport in plasmas in the Galaxy: theory and observations

Onset of Turbulent Fast Magnetic Reconnection Observed in the Solar Atmosphere

Topological theory of physical fields

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