Speaker
Luca Del Zanna
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/O5.J601.pdf
The tearing instability in relativistic magnetohydrodynamics
L. Del Zanna1,2,3 , E. Papini1,2 , S. Landi1,2 , M. Bugli4 , N. Bucciantini2,1,3
1 Dipartimento di Fisica e Astronomia, Università di Firenze, Firenze, Italy
2 INAF - Osservatorio Astrofisico di Arcetri, Firenze, Italy
3 INFN - Sezione di Firenze, Firenze, Italy
4 CEA-Saclay, Paris, France
Magnetic energy dissipation in relativistic plasmas is a crucial process operating in many en-
vironments typical of high-energy astrophysics, such as pulsar winds and nebulae, magnetars,
and magnetized disks around black holes. In many cases such dissipation is required to be of
explosive type, given that flaring activity is often observed in such objects, in the form of sudden
releases of gamma rays. Here we discuss the role of the aspect ratio of the reconnecting current
sheet, which, as for classic and Hall magnetohydrodynamics (MHD), when sufficiently small
is known to lead to a very rapid evolution of the spontaneous tearing instability and to explo-
sive secondary reconnection events (super-tearing or plasmoid instability). Multi-dimensional
simulations of resistive, relativistic MHD are presented for various magnetizations and plasma
betas, and 2-D results show a quasi-universal evolution, occurring on the ideal (relativistic)
Alfvén time. Extension to the 3-D case and possible applications to the physics of magnetars
and pulsar wind nebulae are briefly discussed.
