Production and Persistence of Extreme Two-temperature Plasmas in Radiative Relativistic Turbulence

Zhdankin, Vladimir; Uzdensky, Dmitri A.; Kunz, Matthew W.

doi:10.3847/1538-4357/abcf31

Title: Production and Persistence of Extreme Two-temperature Plasmas in Radiative Relativistic Turbulence

Full Record
Other Related Research

Abstract

Turbulence is a predominant process for energizing electrons and ions in collisionless astrophysical plasmas, and thus is responsible for shaping their radiative signatures (luminosity, spectra, and variability). To better understand the kinetic properties of a collisionless radiative plasma subject to externally driven turbulence, we investigate particle-in-cell simulations of relativistic plasma turbulence with external inverse Compton cooling acting on the electrons. We find that ions continuously heat up while electrons gradually cool down (due to the net effect of radiation), and hence the ion-to-electron temperature ratio T_i/T_e grows in time. Furthermore, we show that Ti/Te is limited only by the size and duration of the simulations (reaching $${T}_{i}/{T}_{e}\sim {10}^{3}$$), indicating that there are no efficient collisionless mechanisms of electron–ion thermal coupling. This result has implications for models of radiatively inefficient accretion flows, such as observed in the Galactic center and in M87, for which so-called two-temperature plasmas with $${T}_{i}/{T}_{e}\gg 1$$ have been invoked to explain their low luminosity. Additionally, we find that electrons acquire a quasi-thermal distribution (dictated by the competition of turbulent particle energization and radiative cooling), while ions undergo efficient nonthermal acceleration (acquiring a harder distribution than in equivalent nonradiative simulations). There is a modest nonthermal population of high-energy electrons that are beamed intermittently in space, time, and direction; these beamed electrons may explain rapid flares in certain high-energy astrophysical systems (e.g., in the Galactic center). These numerical results demonstrate that extreme two-temperature plasmas can be produced and maintained by relativistic radiative turbulence.

Authors:

Zhdankin, Vladimir ^[1]; Uzdensky, Dmitri A. ^[2]; Kunz, Matthew W. ^[3]

Princeton Univ., NJ (United States)
Univ. of Colorado, Boulder, CO (United States). Center for Integrated Plasma Studies
Princeton Univ., NJ (United States); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Publication Date:: Mon Feb 15 00:00:00 EST 2021

Research Org.:: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Sponsoring Org.:: USDOE Office of Science (SC); National Aeronautics and Space Administration (NASA); National Science Foundation (NSF)

OSTI Identifier:: 1817210

Grant/Contract Number:: AC02-06CH11357; HST-HF2-51426.001-A; NAS5-26555; NNX17AK57G; 80NSSC20K0545; AST-1806084; AST-1715277; ACI-1548562

Resource Type:: Accepted Manuscript

Journal Name:: The Astrophysical Journal (Online)

Additional Journal Information:: Journal Name: The Astrophysical Journal (Online); Journal Volume: 908; Journal Issue: 1; Journal ID: ISSN 1538-4357

Publisher:: IOP Publishing

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; plasma astrophysics; high-energy astrophysics; accretion; non-thermal radiation sources; cosmic rays; relativistic jets

Citation Formats


                    Zhdankin, Vladimir, Uzdensky, Dmitri A., and Kunz, Matthew W. Production and Persistence of Extreme Two-temperature Plasmas in Radiative Relativistic Turbulence.  United States: N. p., 2021. 
Web.  doi:10.3847/1538-4357/abcf31.

Copy to clipboard


                    Zhdankin, Vladimir, Uzdensky, Dmitri A., & Kunz, Matthew W. Production and Persistence of Extreme Two-temperature Plasmas in Radiative Relativistic Turbulence.  United States.  https://doi.org/10.3847/1538-4357/abcf31

Copy to clipboard


                    Zhdankin, Vladimir, Uzdensky, Dmitri A., and Kunz, Matthew W. Mon .  
"Production and Persistence of Extreme Two-temperature Plasmas in Radiative Relativistic Turbulence".  United States.  https://doi.org/10.3847/1538-4357/abcf31.  https://www.osti.gov/servlets/purl/1817210.

Copy to clipboard


                    
@article{osti_1817210,

  title        = {Production and Persistence of Extreme Two-temperature Plasmas in Radiative Relativistic Turbulence},

  author       = {Zhdankin, Vladimir and Uzdensky, Dmitri A. and Kunz, Matthew W.},

  abstractNote = {Turbulence is a predominant process for energizing electrons and ions in collisionless astrophysical plasmas, and thus is responsible for shaping their radiative signatures (luminosity, spectra, and variability). To better understand the kinetic properties of a collisionless radiative plasma subject to externally driven turbulence, we investigate particle-in-cell simulations of relativistic plasma turbulence with external inverse Compton cooling acting on the electrons. We find that ions continuously heat up while electrons gradually cool down (due to the net effect of radiation), and hence the ion-to-electron temperature ratio Ti/Te grows in time. Furthermore, we show that Ti/Te is limited only by the size and duration of the simulations (reaching ${T}_{i}/{T}_{e}\sim {10}^{3}$), indicating that there are no efficient collisionless mechanisms of electron–ion thermal coupling. This result has implications for models of radiatively inefficient accretion flows, such as observed in the Galactic center and in M87, for which so-called two-temperature plasmas with ${T}_{i}/{T}_{e}\gg 1$ have been invoked to explain their low luminosity. Additionally, we find that electrons acquire a quasi-thermal distribution (dictated by the competition of turbulent particle energization and radiative cooling), while ions undergo efficient nonthermal acceleration (acquiring a harder distribution than in equivalent nonradiative simulations). There is a modest nonthermal population of high-energy electrons that are beamed intermittently in space, time, and direction; these beamed electrons may explain rapid flares in certain high-energy astrophysical systems (e.g., in the Galactic center). These numerical results demonstrate that extreme two-temperature plasmas can be produced and maintained by relativistic radiative turbulence.},

  doi          = {10.3847/1538-4357/abcf31},

  journal      = {The Astrophysical Journal (Online)},

  number       = 1,

  volume       = 908,

  place        = {United States},

  year         = {Mon Feb 15 00:00:00 EST 2021},

  month        = {Mon Feb 15 00:00:00 EST 2021}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (DOE)

Publisher's Version of Record

https://doi.org/10.3847/1538-4357/abcf31

Other availability

Search WorldCat to find libraries that may hold this journal

Save / Share:

Export Metadata

Save to My Library

Similar Records in DOE PAGES and OSTI.GOV collections:

Synchrotron Firehose Instability

Journal Article Zhdankin, Vladimir ; Kunz, Matthew W. ; Uzdensky, Dmitri A. - The Astrophysical Journal

We demonstrate using linear theory and particle-in-cell (PIC) simulations that a synchrotron-cooling collisionless plasma acquires pressure anisotropy and, if the plasma beta is sufficiently high, becomes unstable to the firehose instability, in a process that we dub the synchrotron firehose instability (SFHI). The SFHI channels free energy from the pressure anisotropy of the radiating, relativistic electrons (and/or positrons) into small-amplitude, kinetic-scale, magnetic-field fluctuations, which pitch-angle scatter the particles and bring the plasma to a near-thermal state of marginal instability. The PIC simulations reveal a nonlinear cyclic evolution of firehose bursts interspersed by periods of stable cooling. We compare the SFHImore »« less
https://doi.org/10.3847/1538-4357/acaf54

Full Text Available
Spontaneous magnetization of collisionless plasma

Journal Article Zhou, Muni ; Zhdankin, Vladimir ; Kunz, Matthew W. ; ... - Proceedings of the National Academy of Sciences of the United States of America

Here we study within a fully kinetic framework the generation of “seed” magnetic fields through the Weibel instability, driven in an initially unmagnetized plasma by a large-scale shear force. We develop an analytical model that describes the development of thermal pressure anisotropy via phase mixing, the ensuing exponential growth of magnetic fields in the linear Weibel stage, and the saturation of the Weibel instability when the seed magnetic fields become strong enough to instigate gyromotion of particles and thereby inhibit their free-streaming. The predicted scaling dependencies of the saturated fields on key parameters (e.g., ratio of system scale to electronmore »« less
https://doi.org/10.1073/pnas.2119831119

Full Text Available
Particle acceleration in relativistic magnetic reconnection with strong inverse-Compton cooling in pair plasmas

Journal Article Werner, Gregory R. ; Philippov, Alexander A. ; Uzdensky, Dmitri A. - Monthly Notices of the Royal Astronomical Society: Letters

Particle-in-cell (PIC) simulations have shown that relativistic collisionless magnetic reconnection drives non-thermal particle acceleration (NTPA), potentially explaining high-energy (X-ray/γ-ray) synchrotron and/or inverse Compton (IC) radiation observed from various astrophysical sources. The radiation back-reaction force on radiating particles has been neglected in most of these simulations, even though radiative cooling considerably alters particle dynamics in many astrophysical environments where reconnection may be important. We present a radiative PIC study examining the effects of external IC cooling on the basic dynamics, NTPA, and radiative signatures of relativistic reconnection in pair plasmas. We find that, while the reconnection rate and overall dynamics aremore »« less
Cited by 29
https://doi.org/10.1093/mnrasl/sly157
RADIATIVE COOLING IN RELATIVISTIC COLLISIONLESS SHOCKS: CAN SIMULATIONS AND EXPERIMENTS PROBE RELEVANT GAMMA-RAY BURST PHYSICS?

Journal Article Medvedev, Mikhail V ; Spitkovsky, Anatoly - Astrophysical Journal

We address the question of whether numerical particle-in-cell (PIC) simulations and laboratory laser-plasma experiments can (or will be able to, in the near future) model realistic gamma-ray burst (GRB) shocks. For this, we compare the radiative cooling time, t{sub cool}, of relativistic electrons in the shock magnetic fields to the microscopic dynamical time of collisionless relativistic shocks-the inverse plasma frequency of protons, {omega}{sup -1}{sub pp}. We obtain that for t{sub cool}{omega}{sup -1} {sub pp}{approx}< few hundred, the electrons cool efficiently at or near the shock jump and are capable of emitting away a large fraction of the shock energy. Suchmore »« less
https://doi.org/10.1088/0004-637X/700/2/956; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
THE MAXIMUM ENERGY OF ACCELERATED PARTICLES IN RELATIVISTIC COLLISIONLESS SHOCKS

Journal Article Sironi, Lorenzo ; Spitkovsky, Anatoly ; Arons, Jonathan - Astrophysical Journal

The afterglow emission from gamma-ray bursts (GRBs) is usually interpreted as synchrotron radiation from electrons accelerated at the GRB external shock that propagates with relativistic velocities into the magnetized interstellar medium. By means of multi-dimensional particle-in-cell simulations, we investigate the acceleration performance of weakly magnetized relativistic shocks, in the magnetization range 0 {approx}< {sigma} {approx}< 10{sup -1}. The pre-shock magnetic field is orthogonal to the flow, as generically expected for relativistic shocks. We find that relativistic perpendicular shocks propagating in electron-positron plasmas are efficient particle accelerators if the magnetization is {sigma} {approx}< 10{sup -3}. For electron-ion plasmas, the transition tomore »« less
https://doi.org/10.1088/0004-637X/771/1/54

Similar Records