On the magnetic field orientation and plasma flows in solar filament barbs

Speeds of vertical flows in quiescent solar filaments are typically much le ss than the local Alfven speed. This is why the flows in filament barbs can be modeled by perturbing a magnetostatic solution describing a balance bet ween the Lorentz force, gravity, and gas pressure in a barb. This approach explains why some of the flows are neither aligned with the magnetic field nor controlled by gravity. Both the observed upflows and the magnetic field dips in barbs are likely to be caused by photospheric magnetic reconnectio n.