Influence of tearing instability on magnetohydrodynamic turbulence

Abstract

It was proposed recently by Loureiro and Boldyrev [Phys. Rev. Lett. 118, 245101 (2017)PRLTAO0031-900710.1103/PhysRevLett.118.245101] and Mallet et al. [Mon. Not. R. Astron. Soc. 468, 4862 (2017)MNRAA40035-871110.1093/mnras/stx670] that strongly anisotropic current sheets formed in the inertial range of magnetohydrodynamic turbulence become affected by the tearing instability at scales smaller than a critical scale λ_{c}, and larger than the dissipation scale of turbulence. If true, this process can modify the nature of energy cascade at smaller scales, leading to a new, tearing-mediated regime of magnetohydrodynamic (MHD) turbulence. In this work, we present a numerical study of strongly anisotropic, two-dimensional turbulent eddies, and we demonstrate that the tearing instability can indeed compete with their nonlinear evolution. The results, therefore, provide direct numerical support for the picture that a new regime of MHD turbulence can exist below λ_{c}.