Experimental evidence of existence of the axial magnetic field in a plasma focus V. I. Krauz, K. N. Mitrofanov, M. Scholz, M. Paduch, P. Kubes, L. Karpinski and E. Zielinska EPL, 98 4 (2012) 45001 Published online: 30 May 2012 DOI: 10.1209/0295-5075/98/45001