ARE THE NONLOCAL EFFECTS REALLY ACTUAL FOR THE HTSC

Recently a new trend in theoretical works has appeared which claims th at tile nonlocal effects may be relevant for the HTSC, containing high -J(c) weak links (twin boundaries, stacking faults etc.). In such weak links a new type of vortices - Abrikosov-Josephson (AJ) vortices - ma y arise and move freely along the defects, leading to dissipation. In the present work the first observation of a steep non-linear dependenc e of the surface resistance R(s) of YBaCuO thin film and high quality ceramic on microwave magnetic field amplitude H-omega, which is a uniq ue feature for the dissipation due to the current-driven oscillation o f Al-vortex, is reported. At the same time the dependence R(beta)(H-om ega) is well described by the current-induced critical state model pro posed by Sridhar. Additional experiments which may help to distinguish between the two models are discussed.