Particle acceleration by relativistic magnetic reconnection driven by kink instability turbulence in Poynting flux dominated jets. (arXiv:2009.08516v5 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Medina_Torrejon_T/0/1/0/all/0/1">Tania E. Medina-Torrejon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pino_E/0/1/0/all/0/1">Elisabete M. de Gouveia Dal Pino</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kadowaki_L/0/1/0/all/0/1">Luis H.S. Kadowaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kowal_G/0/1/0/all/0/1">Grzegorz Kowal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Singh_C/0/1/0/all/0/1">Chandra B. Singh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mizuno_Y/0/1/0/all/0/1">Yosuke Mizuno</a>
Particle acceleration in magnetized relativistic jets still puzzles
theorists, specially when one tries to explain the highly variable emission
observed in blazar jets or gamma-ray bursts putting severe constraints on
current models. In this work we investigate the acceleration of particles
injected in a three-dimensional relativistic magnetohydrodynamical jet subject
to current driven kink instability (CDKI), which drives turbulence and fast
magnetic reconnection. Test protons injected in the nearly stationary snapshots
of the jet, experience an exponential acceleration up to a maximum energy. For
a background magnetic field of $B sim 0.1$ G, this saturation energy is $sim
10^{16}$ eV, while for $B sim 10$ G it is $sim 10^{18}$ eV. The simulations
also reveal a clear association of the accelerated particles with the regions
of fast reconnection. In the early stages of the development of the non-linear
growth of CDKI in the jet, when there are still no sites of fast reconnection,
injected particles are also efficiently accelerated, but by magnetic curvature
drift in the wiggling jet spine. However, they have to be injected with an
initial energy much larger than that required for particles to accelerate in
reconnection sites. Finally, we have also obtained from the simulations an
acceleration time due to reconnection with a weak dependence on the particles
energy $E$, $t_A propto E^{0.1}$. The energy spectrum of the accelerated
particles develops a high energy tail with a power law index $p sim$ -1.2 in
the beginning of the acceleration, in agreement with earlier works. Our results
provide an appropriate multi-dimensional framework for exploring this process
in real systems and explain their complex emission patterns, specially in the
very high energy bands and the associated neutrino emission recently detected
in some blazars.
Particle acceleration in magnetized relativistic jets still puzzles
theorists, specially when one tries to explain the highly variable emission
observed in blazar jets or gamma-ray bursts putting severe constraints on
current models. In this work we investigate the acceleration of particles
injected in a three-dimensional relativistic magnetohydrodynamical jet subject
to current driven kink instability (CDKI), which drives turbulence and fast
magnetic reconnection. Test protons injected in the nearly stationary snapshots
of the jet, experience an exponential acceleration up to a maximum energy. For
a background magnetic field of $B sim 0.1$ G, this saturation energy is $sim
10^{16}$ eV, while for $B sim 10$ G it is $sim 10^{18}$ eV. The simulations
also reveal a clear association of the accelerated particles with the regions
of fast reconnection. In the early stages of the development of the non-linear
growth of CDKI in the jet, when there are still no sites of fast reconnection,
injected particles are also efficiently accelerated, but by magnetic curvature
drift in the wiggling jet spine. However, they have to be injected with an
initial energy much larger than that required for particles to accelerate in
reconnection sites. Finally, we have also obtained from the simulations an
acceleration time due to reconnection with a weak dependence on the particles
energy $E$, $t_A propto E^{0.1}$. The energy spectrum of the accelerated
particles develops a high energy tail with a power law index $p sim$ -1.2 in
the beginning of the acceleration, in agreement with earlier works. Our results
provide an appropriate multi-dimensional framework for exploring this process
in real systems and explain their complex emission patterns, specially in the
very high energy bands and the associated neutrino emission recently detected
in some blazars.
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