Imaging of dense plasma microdomains (in plasma focus discharges) with thin magnetic films

Summary form only given. Imaging of plasma domains (high ion and energy density; PDER) with simultaneous definition of its domain characteristics can provide critical information about exotic plasma states. In the demonstration tests, a thin film disc of magnetic garnets, TF-MG, was used. In particular, (BiTm)/sub 3/(FeGa)/sub 5/O/sub 12/ garnet films (dia. 76 mm, h=7 /spl mu/m equivalent to 1 MeV D/sup +/ range, stripe domain period 50 /spl mu/m, 4/spl pi/M<100 G, magnetic anisotropy field <2 kG, Faraday rotation /spl sime/4/spl deg/ in visible light) have been grown (at Bialystok University) by liquid phase epitaxy method on a Gd-Ga garnet substrate; [111] plane. Implanted ions permanently change the magnetic pattern of domains and induce local changes of magnetic properties. Evaluation was performed using Faraday effect with specially developed magneto-optical microscopy (differential enlargement, digital image processing) and local magneto-optical magnetometry. This technique allows us to visualize the spot of implanted ions and define the distribution-in-depth of implanted-ions density and energy. For PDER on-impact-imaging the TF-MG sample was covered with Mylar (h=12 /spl mu/m; equivalent to 1 MeV D/sup +/ range) and exposed to a single plasma focus discharge at Compton Labs. (W=7 kJ, p=4 Torr of D/sub 2/, neutron field 0.5-1/spl times/10/sup 9/, anode end-TF-MG distance 1=15 cm).