Kinetic Study of Radiation-Reaction-Limited Particle Acceleration During the Relaxation of Unstable Force-Free Equilibria

Yuan, Yajie; Nalewajko, Krzysztof; Zrake, Jonathan; East, William E.; Blandford, R. D.

doi:10.3847/0004-637x/828/2/92

Cited by 62 publications

(78 citation statements)

References 48 publications

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“…In either case, turbulence statistics at high σ can be compared to force-free MHD, which resembles the non-relativistic case (Thompson & Blaes 1998;Cho 2005;Cho & Lazarian 2013). We note these considerations do not preclude transient relativistic motions from developing in decaying turbulence without an energy sink, which may better represent many astrophysical systems (where turbulence occurs in outflowing plasma (e.g., Zrake 2016) or is impulsively triggered by instabilities (e.g., Nalewajko et al 2016;Yuan et al 2016)). …”

Section: Discussionmentioning

confidence: 99%

Numerical investigation of kinetic turbulence in relativistic pair plasmas – I. Turbulence statistics

Zhdankin

Uzdensky

Werner

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We describe results from particle-in-cell simulations of driven turbulence in collisionless, magnetized, relativistic pair plasma. This physical regime provides a simple setting for investigating the basic properties of kinetic turbulence and is relevant for high-energy astrophysical systems such as pulsar wind nebulae and astrophysical jets. In this paper, we investigate the statistics of turbulent fluctuations in simulations on lattices of up to 1024 3 cells and containing up to 2 × 10 11 particles. Due to the absence of a cooling mechanism in our simulations, turbulent energy dissipation reduces the magnetization parameter to order unity within a few dynamical times, causing turbulent motions to become sub-relativistic. In the developed stage, our results agree with predictions from magnetohydrodynamic turbulence phenomenology at inertial-range scales, including a power-law magnetic energy spectrum with index near −5/3, scaledependent anisotropy of fluctuations described by critical balance, log-normal distributions for particle density and internal energy density (related by a 4/3 adiabatic index, as predicted for an ultra-relativistic ideal gas), and the presence of intermittency. We also present possible signatures of a kinetic cascade by measuring power-law spectra for the magnetic, electric, and density fluctuations at sub-Larmor scales.

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Section: Discussionmentioning

confidence: 99%

Numerical investigation of kinetic turbulence in relativistic pair plasmas – I. Turbulence statistics

Zhdankin

Uzdensky

Werner

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…Extensive and detailed computations have recently been presented by Yuan et al 2016 concerning the link between macroscopic field configurations with higher magnetization and kinetic conditions conducive to acceleration. We conclude that a slow time shift of macroscopic conditions toward increased σ j and sheared B topology can end up into triggering and enhancing local accelerations governed by high values of σ e .…”

Section: The Kinetic Sidementioning

confidence: 99%

Blazar Jets Perturbed by Magneto-gravitational Stresses in Supermassive Binaries

Cavaliere

Tavani

Vittorini

2017

ApJ

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We study particle acceleration and radiative processes in Blazar jets under recurring conditions set by gravitational perturbations in supermassive binary systems. We consider the action from a companion orbiting a primary black hole of ∼ 10 8 M , and perturbing its relativistic jet. We discuss how such conditions induce repetitive magneto-hydrodynamic stresses along the jet, and affect its inner electron acceleration and radiative processes. Specifically, we study how macroscopic perturbations related to increased jet "magnetization" end up into higher radiative outputs in the optical, X-ray and gamma-ray bands. We find first an increase in magnetic field strength as gauged in the optical band from the Synchrotron emission of electrons accelerated in kinetic processes stimulated by reconnecting magnetic lines. The energetic electrons then proceed to up-scatter the Synchrotron photons to GeV energies after the canonical Synchrotron-Self Compton radiation process. Our model implies a specific, recurring pattern in the optical to gamma-ray emissions, made of high peaks and wide troughs. Progressing accelerations caused by spreading reconnections will produce an additional Synchrotron keV component. Such outbursts provide a diagnostics for enhanced acceleration of electrons which can up-scatter photons into the TeV range. We discuss how our model applies to the BL Lac object PG 1553+113, arguably the best candidate to now for high amplitude, recurring modulations in its gamma-ray emissions. We also consider other BL Lacs showing correlated keV -TeV radiations such as Mrk 421.

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“…The terms on the first line represent the Hededal (2005) radiation reaction force used by many other authors (Sironi & Spitkovsky 2009;Cerutti et al 2013Cerutti et al , 2014Yuan et al 2016). These terms typically dominate the radiation reaction force, but we include the additional reduced Landau-Lifshitz terms on the second line to increase the accuracy of the simulation without significant computational cost.…”

Section: Radiative Feedbackmentioning

confidence: 99%

“…Several researchers have used PIC codes with a form of the radiation reaction force included (Hededal 2005;Tamburini et al 2010) to investigate the effects of cooling 4 on particle acceleration in relativistic reconnection (Cerutti et al 2013, 4 Jaroschek & Hoshino (2009) use a PIC simulation including another form 2014; Yuan et al 2016). They find that relativistic reconnection produces beamed particles and highly variable radiation above the synchrotron burnoff limit in both two (Cerutti et al 2013;Yuan et al 2016) and three (Cerutti et al 2014) dimensions.…”

Section: Introductionmentioning

confidence: 99%

“…They find that relativistic reconnection produces beamed particles and highly variable radiation above the synchrotron burnoff limit in both two (Cerutti et al 2013;Yuan et al 2016) and three (Cerutti et al 2014) dimensions. Relativistic reconnection also produces high-energy radiation above the synchrotron burnoff limit in the presence of a guide field Cerutti et al (2013Cerutti et al ( , 2014 as long as it is weaker than the reversing field, and in reconnection produced by the collapse of a two-dimensional flux rope system (Yuan et al 2016). These simulations demonstrate that the production of radiation beyond the synchrotron burnoff limit is robust in relativistic magnetic reconnection.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Cooling on Particle Trajectories and Acceleration in Relativistic Magnetic Reconnection

Kagan

Nakar

Piran

2016

ApJ

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The maximum synchrotron burnoff limit of 160 MeV represents a fundamental limit to radiation resulting from electromagnetic particle acceleration in one-zone ideal plasmas. In magnetic reconnection, however, particle acceleration and radiation are decoupled because the electric field is larger than the magnetic field in the diffusion region. We carry out two-dimensional particle-in-cell simulations to determine the extent to which magnetic reconnection can produce synchrotron radiation above the burnoff limit. We use the test particle comparison (TPC) method to isolate the effects of cooling by comparing the trajectories and acceleration efficiencies of test particles incident on such a reconnection region with and without cooling them. We find that the cooled and uncooled particle trajectories are typically similar during acceleration in the reconnection region, and derive an effective limit on particle acceleration that is inversely proportional to the average magnetic field experienced by the particle during acceleration. Using the calculated distribution of this average magnetic field as a function of uncooled final particle energy, we find analytically that cooling does not affect power-law particle energy spectra except at energies far above the synchrotron burnoff limit. Finally, we compare fully cooled and uncooled simulations of reconnection, confirming that the synchrotron burnoff limit does not produce a cutoff in the particle energy spectrum. Our results indicate that the TPC method accurately predicts the effects of cooling on particle acceleration in relativistic reconnection, and that even far above the burnoff limit, the synchrotron energy of radiation produced in reconnection is not limited by cooling.

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Kinetic Study of Radiation-Reaction-Limited Particle Acceleration During the Relaxation of Unstable Force-Free Equilibria

Cited by 62 publications

References 48 publications

Numerical investigation of kinetic turbulence in relativistic pair plasmas – I. Turbulence statistics

Numerical investigation of kinetic turbulence in relativistic pair plasmas – I. Turbulence statistics

Blazar Jets Perturbed by Magneto-gravitational Stresses in Supermassive Binaries

The Effect of Cooling on Particle Trajectories and Acceleration in Relativistic Magnetic Reconnection

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