2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/198508The expulsion of magnetic flux lines from a growing superconducting core of a quark star has been investigated. The idea of impurity diffusion in molten alloys and an identical mechanism of baryon number transport from hot quark-gluon-plasma phase to hadronic phase during quark-hadron phase transition in the early universe, micro-second after big bang has been used. The possibility of Mullins-Sekerka normal-superconducting interface instability has also been studied.Thoroughly revised version. Accepted for Astrophysics & Space ScienceHigh Energy Physics - Phenomenologytext