The Snake: A Reconnecting Coil in a Twisted Magnetic Flux Tube

Abstract

We propose that the curious Galactic center filament known as the Snake is a twisted giant magnetic flux tube, anchored in rotating molecular clouds. The MHD kink instability generates coils in the tube and subsequent magnetic reconnection injects relativistic electrons. Energy-dependent diffusion of electrons away from the coil produces a flat spectral index at large distances from it. Our fit to the existing data shows that the magnetic field of ∼0.4 mG is large compared to the ambient ∼7 μG field, indicating that the flux tube is force-free. If the relative level of turbulence in the Snake and the general interstellar medium are similar, then electrons have been diffusing in the Snake for about 3 × 105 yr, comparable to the timescale at which magnetic energy is annihilated in the major kink. Estimates of the magnetic field in the G359.19-0.05 molecular complex are similar to our estimate of the magnetic field in the Snake, suggesting a strong connection between the physics of the anchoring molecular regions and the Snake. We suggest that the physical processes considered here may be relevant to other radio filaments near the Galactic center. We also suggest further observations of the Snake and other filaments that would be useful for obtaining further insights into the physics of these objects. Show more