%0 Journal Article
%A Fernández-Rañada, Antonio
%T Ball lightning as a force-free magnetic knot
%D 2000
%@ 1063-651X
%U https://hdl.handle.net/20.500.14352/58974
%X The stability of fireballs in a recent model of ball lightning is studied. It is shown that the balls shine while relaxing in:in almost quiescent expansion, and that three effects contribute to their stability: (i) the formation in each one during a process of Taylor relaxation of a force-free magnetic field, a concept introduced in 1954 in order to explain the existence of large magnetic fields and currents in stable configurations of astrophysical plas,nas; (ii) the so called Alfven conditions in magnetohydrodynamics; and (iii) the approximate conservation of the helicity integral. The force-free fields that appear are termed "knots" because their magnetic lines are closed and linked.
%~