Wakefield Acceleration in a Jet from a Neutrino Driven Accretion Flow around a Black Hole

TL;DR

This paper explores how Alfvénic wave pulses in jets from neutrino-driven accretion flows around black holes can produce wakefield acceleration, leading to high-energy emissions like gamma-ray bursts, neutrinos, and ultra-high-energy protons.

Contribution

It introduces a novel mechanism where episodic accretion-induced Alfvénic pulses generate wakefields that accelerate particles to extreme energies in black hole jets.

Findings

High-energy gamma-ray bursts from accelerated electrons.

Neutrino pulses from accelerated protons.

Protons reaching energies beyond 10^{20} eV.

Abstract

We have investigated electro-magnetic (EM) wave pulses in a jet from a neutrino driven accretion flow (NDAF) around a black hole (BH). NDAFs are massive accretion disks whose accretion rates of $\dot{M}\approx 0.01 - 10 \mathrm{M}_\odot/\mathrm{s}$ for stellar-mass BHs. Such an extreme accretion may produce a collimated relativistic outflow like a magnetically driven jet in active galactic nuclei and micro-quasars. When we consider strong toroidal magnetic field stranded in the inner-region of a NDAF disk and magnetic impulses on the jet, we find that they lead to the emanation of high energy emissions for gamma-ray bursts as well as high energy cosmic rays. When Alfv\'enic wave pulses are generated by episodic immense accretions, it propagates along the large-scale structured magnetic field in the jet. Once the Alfv\'enic wave pulses reach at nearly the speed of light in the underdense condition, it turns into EM wave pulses which produce plasma wakes behind them. These wakefields exert a collective accelerating force synchronous to the motion of particles. As a result, the wakefield acceleration premises various observational signatures, such as pulsating bursts of high energy gamma-rays from accelerated electrons, pulses of neutrinos from accelerated protons, and protons with maximum energies beyond $10^{20}~\mathrm{eV}$.