A NEW METHOD FOR SUPERCONDUCTOR MAGNETIZATION CURVE COMPUTING

A mathematical method using geometrical transformations (reflections a nd translations) on an arbitrary chosen curve - called the profile fun ction - which describes the magnetic field distribution inside the sup erconductor sample is presented. This profile function must be strict monotone increasing and positive. By this method we have calculated th e expression of 'jump' portion that connects the ascending and descend ing field branches and non-primitive minor loops. Also we propose a ne w model (called critical field model) based on a bounded profile funct ion at some value B-cr. explicit expressions for computing all the bra nches of the hysteresis loop are derived. The comparison between the v alues of critical current density computed from the vertical width of the hysteresis loops Delta M and that deduced from the chosen profile function shows a good agreement for B-a > B-p. Finally, we present an exact relation between Delta M and J(c) and its derivatives for an arb itrary positive J(c) function. (C) 1998 Elsevier Science Ltd. All righ ts reserved.