Magnetohydrodynamic kinks in astrophysics

Three-dimensional magnetic kinks in nonresistive plasmas may be created and annihilated in pairs and conserve their homotopy properties during their lifetime. Such kinks could prove relevant to astrophysical, geophysical, or laboratory plasma problems. Magnetic kinks with one axis of rotational invariance are described analytically and graphically. As an example their relevance to the puzzle of the origin of galaxies is examined. (author)