Magnetic Helicity & Taylor Relaxation
A topological invariant measuring the linking, twisting, and tangling of magnetic flux lines in a closed plasma volume.
Governing formula
K = ∭ A · B dV, ∇ × B = μ B (Taylor State)
SI unit
Wb² (Magnetic Helicity Units)
In depth
In highly conductive plasmas, magnetic helicity K is conserved during magnetic reconnection. According to J.B. Taylor, a turbulent plasma relaxes to a minimum magnetic energy state (Taylor state) satisfying force-free field ∇ × B = μ B.
Examples in the real world
Spontaneous self-organization of plasma into force-free configurations in Reversed Field Pinches and Spheromaks.