Weak Alfv’enic turbulence in relativistic plasmas II: Current sheets and dissipation. (arXiv:2105.01145v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Ripperda_B/0/1/0/all/0/1">B. Ripperda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mahlmann_J/0/1/0/all/0/1">J.F. Mahlmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chernoglazov_A/0/1/0/all/0/1">A. Chernoglazov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+TenBarge_J/0/1/0/all/0/1">J.M. TenBarge</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Most_E/0/1/0/all/0/1">E.R. Most</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Juno_J/0/1/0/all/0/1">J. Juno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yuan_Y/0/1/0/all/0/1">Y. Yuan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Philippov_A/0/1/0/all/0/1">A.A. Philippov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bhattacharjee_A/0/1/0/all/0/1">A. Bhattacharjee</a>
Alfv’en waves as excited in black hole accretion disks and neutron star
magnetospheres are the building blocks of turbulence in relativistic,
magnetized plasmas. A large reservoir of magnetic energy is available in these
systems, such that the plasma can be heated significantly even in the weak
turbulence regime. We perform high-resolution three-dimensional simulations of
two counter-propagating Alfv’en waves, showing that an
$E_{B_{perp}}(k_{perp}) propto k_{perp}^{-2}$ energy spectrum develops as a
result of the weak turbulence cascade in relativistic magnetohydrodynamics and
its infinitely magnetized (force-free) limit. The plasma turbulence
ubiquitously generates current sheets, which act as locations where magnetic
energy dissipates. We study magnetic reconnection as a dissipation mechanism
and show that current sheets form as a natural result of nonlinear interactions
between counter-propagating Alfv’en waves. These current sheets form due to
the compression of elongated eddies, driven by the shear induced by growing
higher order modes, and undergo a thinning process until they break-up into
small-scale turbulent structures. We explore the formation of extended
reconnection regions both in overlapping waves and in localized wave packet
collisions. The relativistic interaction of localized Alfv’en waves induces
both Alfv’en waves and fast waves and efficiently mediates the conversion and
dissipation of electromagnetic energy in astrophysical systems. Plasma
energization through reconnection in current sheets emerging during the
interaction of Alfv’en waves can potentially explain X-ray emission in black
hole accretion coronae and neutron star magnetospheres.
Alfv’en waves as excited in black hole accretion disks and neutron star
magnetospheres are the building blocks of turbulence in relativistic,
magnetized plasmas. A large reservoir of magnetic energy is available in these
systems, such that the plasma can be heated significantly even in the weak
turbulence regime. We perform high-resolution three-dimensional simulations of
two counter-propagating Alfv’en waves, showing that an
$E_{B_{perp}}(k_{perp}) propto k_{perp}^{-2}$ energy spectrum develops as a
result of the weak turbulence cascade in relativistic magnetohydrodynamics and
its infinitely magnetized (force-free) limit. The plasma turbulence
ubiquitously generates current sheets, which act as locations where magnetic
energy dissipates. We study magnetic reconnection as a dissipation mechanism
and show that current sheets form as a natural result of nonlinear interactions
between counter-propagating Alfv’en waves. These current sheets form due to
the compression of elongated eddies, driven by the shear induced by growing
higher order modes, and undergo a thinning process until they break-up into
small-scale turbulent structures. We explore the formation of extended
reconnection regions both in overlapping waves and in localized wave packet
collisions. The relativistic interaction of localized Alfv’en waves induces
both Alfv’en waves and fast waves and efficiently mediates the conversion and
dissipation of electromagnetic energy in astrophysical systems. Plasma
energization through reconnection in current sheets emerging during the
interaction of Alfv’en waves can potentially explain X-ray emission in black
hole accretion coronae and neutron star magnetospheres.
http://arxiv.org/icons/sfx.gif
