SIZE EFFECT IN CIRCULARLY SYMMETRICAL, ANNULAR JOSEPHSON-JUNCTIONS AND THE ROLE OF AN APPLIED MAGNETIC-FIELD

The size effect in circularly symmetric, annular Josephson junctions is discussed in detail. For a junction of width W, we find that there exists a minimum inner radius rho(min) for resonant soliton motion within the junction, with respect to the dissipative parameter and external magnetic field, and that the applied magnetic field plays an important role in reducing the size effect (rho(min) decreases remarkably in the presence of a negative external magnetic field). Because of the size effect, the range of the first current step vanishes if the inner radius of the annular junction is smaller than rho(min). A qualitative interpretation is given for the size effect. On the basis of our results, future physical experiments are suggested.