PIRSA:13030078 Scientific Series Strong Gravity

DOI10.48660/13030078

Series: Strong Gravity

Sironi, L. (2013). Particle Acceleration by Magnetic Reconnection in Striped Pulsar Winds and Relativistic Jets. Perimeter Institute. https://pirsa.org/13030078

Sironi, Lorenzo. Particle Acceleration by Magnetic Reconnection in Striped Pulsar Winds and Relativistic Jets. Perimeter Institute, Mar. 21, 2013, https://pirsa.org/13030078 

@misc{ pirsa_PIRSA:13030078,
  doi = {10.48660/13030078},
  url = {https://pirsa.org/13030078},
  author = {Sironi, Lorenzo},
  keywords = {Strong Gravity},
  language = {en},
  title = {Particle Acceleration by Magnetic Reconnection in Striped Pulsar Winds and Relativistic Jets},
  publisher = {Perimeter Institute},
  year = {2013},
  month = {mar},
  note = {PIRSA:13030078 see, \url{https://pirsa.org}}
}

Abstract

The relativistic wind of pulsars consists of toroidal stripes of opposite magnetic field polarity, separated by current sheets of hot plasma. By means of 2D and 3D particle-in-cell simulations, we investigate particle acceleration and magnetic field dissipation at the termination shock of a striped pulsar wind. At the shock, the flow compresses and the alternating fields annihilate by driven magnetic reconnection. Irrespective of the stripe wavelength "lambda" or the wind magnetization "sigma" (in the regime sigma>>1 of magnetically-dominated flows), shock-driven reconnection transfers all the magnetic energy of the alternating fields to the particles. As the value of lambda/(r_L*sigma) increases (here, r_L is the relativistic Larmor radius in the wind), the post-shock spectrum passes from a thermal Maxwellian to a flat power-law tail with slope around -1.5, populated by particles accelerated by the reconnection electric field. The limit lambda/(r_L*sigma)>>1 is realized in relativistic jets, where kink instabilities may seed the conditions for magnetic reconnection. Here, we find that the particle spectrum in the current sheet approaches a flat power-law tail with slope between -1.5 and -2, regardless of the conditions in the jet. The spectrum extends to higher energies for larger magnetizations or colder plasma temperatures, everything else being fixed. Our results place important constraints on the emission models of Pulsar Wind Nebulae and magnetically-dominated astrophysical jets.

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