Three-dimensional tearing instability of flux-tube-like magnetic fields

by Vinay Kumar (ICTS / Nordita)

Wednesday 15 Apr 2026, 15:00 → 16:00 Europe/Stockholm

Magnetic reconnection plays a central role in high-energy astrophysical systems, often driven by the tearing instability. While well understood in two dimensions, its behavior in three dimensions is less clear. In this talk, I present a minimal three-dimensional extension to the tearing instability based on a flux-tube-like magnetic configuration obtained by modulating a 2-D current sheet. Using linear theory, eigenvalue analysis, and direct numerical simulations, we show that tearing-like modes persist even in the absence of a guide field. While the dispersion relation retains its characteristic 2-D scaling, the growth rates are systematically reduced due to modulation-induced variations in the inner resistive layer. The resulting dynamics remain quasi-2-D locally, while exhibiting a coherent global 3-D structure, providing a step toward understanding reconnection in realistic astrophysical plasmas.