Evolution of 3-dimensional Relativistic Current Sheets and Development of Self-Generated Turbulence

TL;DR

This study uses 3D relativistic magnetohydrodynamic simulations to show that current sheets in Poynting-dominated plasma develop turbulence instead of plasmoid chains, with implications for high-energy astrophysical phenomena.

Contribution

First 3D simulation demonstrating the transition from plasmoid chains to turbulence in relativistic current sheets, challenging previous 2D assumptions.

Findings

Current sheets evolve into turbulence, not plasmoid chains.

Reconnection rate is approximately 0.004, much lower than in 2D plasmoid scenarios.

Energy conversion to turbulence is minimal, about 0.01%.

Abstract

In this paper, the temporal evolution of 3-dimensional relativistic current sheets in Poynting-dominated plasma is studied for the first time. Over the past few decades, a lot of efforts have been conducted on studying the evolution of current sheets in 2-dimensional space, and concluded that sufficiently long current sheets always evolves into the so-called "plasmoid-chain", which provides fast reconnection rate independent of its resistivity. However, it is suspected that plasmoid-chain can exist only in the case of 2-dimensional approximation, and would show transition to turbulence in 3-dimensional space. We performed 3-dimensional numerical simulation of relativistic current sheet using resistive relativistic magnetohydrodynamic approximation. The results showed that the 3-dimensional current sheet evolve not into plasmoid-chain but turbulence. The resulting reconnection rate is $0.004$ which is much smaller than that of plasmoid-chain. The energy conversion from magnetic field to kinetic energy of turbulence is just 0.01\% which is much smaller than typical non-relativistic cases. Using the energy principle, we also showed that the plasmoid is always unstable for a displacement in opposite direction to its acceleration, probably interchange-type instability, and this always results in seeds of turbulence behind the plasmoids. Finally, the temperature distribution along the sheet is discussed, and it is found that the sheet is less active than plasmoid-chain. Our finding can be applied for many high energy astrophysical phenomena, and can provide a basic model of the general current sheet in Poynting-dominated plasma.