We clarify the notion of magnetic field lines in plasma by referring to sub-microscale (quantum mechanical) particle dynamics. It is demonstrated that magnetic field lines in a field of strength B carry single magnetic flux quanta Ф0 = h/e . The radius of a field line in the given magnetic field B is calculated. It is shown that such field lines can merge and annihilate only over the length ℓ‖ of their strictly anti-parallel sections, for which case we estimate the power generated. The length ℓ‖ becomes a function of the inclination angle θ of the two merging magnetic flux tubes (field lines). Merging is possible only in the interval 1/2 π <θ >≤ π . This provides a sub-microscopic basis for “component reconnection” in classical macro-scale reconnection. We also find that the magnetic diffusion coefficient in plasma appears in quanta Dm0 = eФ0 /me = h/me . This lets us conclude that the bulk perpendicular plasma resistivity is limited and cannot be less than η0⊥ = μ0 Ф0 /me = μ0 h/m e ∼ 10−9 Ohm m. This resistance is an invariant.
Treumann, R. A.; Nakamura, R.; and Baumjohann, W., "Flux Quanta, Magnetic Field Lines, Merging – Some Sub-Microscale Relations of Interest in Space Plasma Physics" (2011). Open Dartmouth: Faculty Open Access Articles. 2701.