Topics in Microphysics of Relativistic Plasmas

Abstract

Astrophysical plasmas can have parameters vastly different from the more studied laboratory and space plasmas. In particular, the magnetic fields can be the dominant component of the plasma, with energy-density exceeding the particle rest-mass energy density. Magnetic fields then determine the plasma dynamical evolution, energy dissipation and acceleration of non-thermal particles. Recent data coming from astrophysical high energy missions, like magnetar bursts and Crab nebula flares, point to the importance of magnetic reconnection in these objects.In this review we outline a broad spectrum of problems related to the astrophysical relevant processes in magnetically dominated relativistic plasmas. We discuss the problems of large scale dynamics of relativistic plasmas, relativistic reconnection and particle acceleration at reconnecting layers, turbulent cascade in force-fee plasmas. A number of astrophysical applications are also discussed.

Relativistic magnetic reconnection in collisionless ion-electron plasmas explored with particle-in-cell simulations

“…We note that magnetar magnetospheres, even if they feature magnetizations exceeding σ cold e = 10 13 (Lyutikov & Lazarian 2013), support a very different reconnection regime due to pair and photon creations (Uzdensky 2011).…”

“…Such attributes made it attractive for high-energy astrophysics to explain, for example, radiation (Romanova & Lovelace 1992) and flares (Giannios et al 2009) in active galactic nuclei (AGNs) jets or in gamma-ray bursts (Lyutikov 2006a;Lazar et al 2009), the heating of AGN and microquasar coronae and associated flares (Di Matteo 1998;Merloni & Fabian 2001;Goodman & Uzdensky 2008;Reis & Miller 2013), the flat radio spectra from galactic nuclei and AGNs (Birk et al 2001), the heating of the lobes of giant radio galaxies (Kronberg et al 2004), the σ-paradox and particle acceleration at pulsar wind termination shocks (Kirk & Skjaeraasen 2003;Pétri & Lyubarsky 2007;Sironi & Spitkovsky 2011), GeV flares from the Crab nebula (Cerutti et al 2012a(Cerutti et al ,b, 2013, transient outflow production in microquasars and quasars (de Gouveia dal Pino & Lazarian 2005;de Gouveia Dal Pino et al 2010;Kowal et al 2011;Dexter et al 2014), gamma-ray burst outflows and non-thermal emissions (Drenkhahn & Spruit 2002;McKinney & Uzdensky 2012), X-ray flashes (Drenkhahn & Spruit 2002), soft gamma-ray repeaters (Lyutikov 2006b;Uzdensky 2011), flares in double pulsar systems (Lyutikov & Lazarian 2013), or energy extraction in the ergosphere of black holes (Koide & Arai 2008).…”

Turbulent reconnection and its implications

“…The suggestion that LV99 is applicable to relativistic reconnection motivated the use of the model for explaining γ-ray bursts [36,119] and in accretion discs around black holes and pulsars [120,121]. Now, as the extension of the model to relativistic case has been confirmed, these and other cases where the relativistic analogue of LV99 process was discussed to be applicable [21] are given numerical support.…”

2D Relativistic MHD simulations of the Kruskal–Schwarzschild instability in a relativistic striped wind

“…In general, magnetic reconnection that does not necessarily result from having a striped-wind configuration has also been invoked in many works over the traditional internal-shock scenario to explain the prompt GRB emission due to it being more efficient in strongly magnetized flows (e.g. Thompson 1994;Lyutikov & Blandford 2003;Giannios & Spruit 2006;Lyutikov 2006;Zhang & Yan 2011).…”

“…Astrophysical plasmas near compact objects are inherently relativistic and collisionless (e.g. Lyutikov & Lazarian 2013), and they require some source of anomalous resistivity in order for reconnection to proceed. The rate of reconnection is set by the inflow velocity v in = β in c of the magnetized fluid into the current layer.…”