Relativistic Magnetic Reconnection in Pair Plasmas and Its Astrophysical Applications

Kagan, Daniel; Sironi, Lorenzo; Cerutti, Benoît; Giannios, Dimitrios

doi:10.1007/978-1-4939-3550-5_16

Cited by 5 publications

(8 citation statements)

References 112 publications

(48 reference statements)

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“…The dynamics is dominated by driven tearing and by drift-kink instabilities, and the flare event is seen when the beam of accelerated particles is close to the assumed line-of-sight in the periodic simulation box (Sironi & Spitkovsky 2014; Kagan et al. 2015; Lyutikov et al. 2016; Sironi, Giannios & Petropoulou 2016; Yuan et al.…”

Section: The Big Open Problems In Pwn Physicsmentioning

confidence: 99%

Multi-D magnetohydrodynamic modelling of pulsar wind nebulae: recent progress and open questions

et al. 2016

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In the last decade, the relativistic magnetohydrodynamic (MHD) modelling of pulsar wind nebulae, and of the Crab nebula in particular, has been highly successful, with many of the observed dynamical and emission properties reproduced down to the finest detail. Here, we critically discuss the results of some of the most recent studies: namely the investigation of the origin of the radio emitting particles and the quest for the acceleration sites of particles of different energies along the termination shock, by using wisps motion as a diagnostic tool; the study of the magnetic dissipation process in high magnetization nebulae by means of new longterm three-dimensional simulations of the pulsar wind nebula evolution; the investigation of the relativistic tearing instability in thinning current sheets, leading to fast reconnection events that might be at the origin of the Crab nebula gamma-ray flares.

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Section: The Big Open Problems In Pwn Physicsmentioning

confidence: 99%

Multi-D magnetohydrodynamic modelling of pulsar wind nebulae: recent progress and open questions

et al. 2016

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“…2016), particle acceleration in jets and pulsar winds (Cerutti, Uzdensky & Begelman 2012; Kagan et al. 2015; Werner et al. 2016), magnetized turbulence (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…It involves a rapid topological rearrangement of the magnetic field, leading to efficient magnetic energy conversion and dissipation. Solar flares (Shibata & Magara 2011) and sawtooth crashes in tokamaks (Hastie 1997) are two popular examples of processes where reconnection plays a key role; others include substorms in the Earth's magnetosphere (Dungey 1961;Burch et al 2016), particle acceleration in jets and pulsar winds (Cerutti, Uzdensky & Begelman 2012;Kagan et al 2015;Werner et al 2016), magnetized turbulence (e.g. Matthaeus & Lamkin 1986;Servidio et al 2009;Zhdankin et al 2013;Cerri & Califano 2017;Loureiro & Boldyrev 2017;Mallet, Schekochihin & Chandran 2017), etc.…”

Section: Introductionmentioning

confidence: 99%

Plasmoid instability in the semi-collisional regime

Bhat

Loureiro

2018

J. Plasma Phys.

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We investigate analytically and numerically the semi-collisional regime of the plasmoid instability, defined by the inequality $\unicode[STIX]{x1D6FF}_{\text{SP}}\gg \unicode[STIX]{x1D70C}_{s}\gg \unicode[STIX]{x1D6FF}_{\text{in}}$, where $\unicode[STIX]{x1D6FF}_{\text{SP}}$ is the width of a Sweet–Parker current sheet, $\unicode[STIX]{x1D70C}_{s}$ is the ion sound Larmor radius and $\unicode[STIX]{x1D6FF}_{\text{in}}$ is the width of the boundary layer that arises in the plasmoid instability analysis. Theoretically, this regime is predicted to exist if the Lundquist number $S$ and the length of the current sheet $L$ are such that $(L/\unicode[STIX]{x1D70C}_{s})^{14/9}<S<(L/\unicode[STIX]{x1D70C}_{s})^{2}$ (for a sinusoidal-like magnetic configuration; for a Harris-type sheet the lower bound is replaced with $(L/\unicode[STIX]{x1D70C}_{s})^{8/5}$). These bounds are validated numerically by means of simulations using a reduced gyrokinetic model (Zocco & Schekochihin, Phys. Plasmas, vol. 18 (10), 2011, 102309) conducted with the code Viriato. Importantly, this regime is conjectured to allow for plasmoid formation at relatively low, experimentally accessible, values of the Lundquist number. Our simulations obtain plasmoid instability at values of $S$ as low as ${\sim}250$. The simulations do not prescribe a Sweet–Parker sheet; rather, one is formed self-consistently during the nonlinear evolution of the initial tearing mode configuration. This proves that this regime of the plasmoid instability is realizable, at least at the relatively low values of the Lundquist number that are accessible to current dedicated experiments.

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“…As long as the flow remains highly magnetized this suppresses internal shocks. On the other hand, in high-σ outflows there is an alternative dissipation mechanism that can be more efficient than internal shocks-magnetic reconnection (Thompson 1994;Spruit et al 2001;Lyutikov & Blandford 2003;Giannios & Spruit 2007;Lyubarsky 2010;Kagan et al 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Recent simulations of relativistic magnetic reconnection suggest that as σ increases, both the reconnection rate and resulting particle bulk velocities (b¢) increase, and the powerlaw index of their energy spectrum becomes harder (Cerutti et al 2012(Cerutti et al , 2014Sironi & Spitkovsky 2014;Guo et al 2015;Kagan et al 2015;Liu et al 2015). In high-σ GRB outflows one may typically expect a G¢~few to several.…”

Section: Introductionmentioning

confidence: 99%

Gamma-Ray Bursts From Magnetic Reconnection: Variability and Robustness of Light Curves

Granot

2016

ApJL

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The dissipation mechanism that powers gamma-ray bursts (GRBs) remains uncertain almost half a century after their discovery. The two main competing mechanisms are the extensively studied internal shocks and the less studied magnetic reconnection. Here we consider GRB emission from magnetic reconnection accounting for the relativistic bulk motions that it produces in the jetʼs bulk rest frame. Far from the source the magnetic field is almost exactly normal to the radial direction, suggesting locally quasi-spherical thin reconnection layers between regions of oppositely directed magnetic field. We show that if the relativistic motions in the jetʼs frame are confined to such a quasi-spherical uniform layer, then the resulting GRB light curves are independent of their direction distribution within this layer. This renders previous results for a delta-function velocity-direction distribution applicable to a much more general class of reconnection models, which are suggested by numerical simulations. Such models that vary in their velocity-direction distribution differ mainly in the size of the bright region that contributes most of the observed flux at a given emission radius or observed time. The more sharply peaked this distribution, the smaller this bright region, and the stronger the light curve variability that may be induced by deviations from a uniform emission over the thin reconnection layer, which may be expected in a realistic GRB outflow. This is reflected both in the observed image at a given observed time and in the observer-frame emissivity map at a given emission radius, which are calculated here for three simple velocity-direction distributions.

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Relativistic Magnetic Reconnection in Pair Plasmas and Its Astrophysical Applications

Cited by 5 publications

References 112 publications

Multi-D magnetohydrodynamic modelling of pulsar wind nebulae: recent progress and open questions

Multi-D magnetohydrodynamic modelling of pulsar wind nebulae: recent progress and open questions

Plasmoid instability in the semi-collisional regime

Gamma-Ray Bursts From Magnetic Reconnection: Variability and Robustness of Light Curves

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