WHAT IS THE CONTRIBUTION OF ELECTRICAL-FIELD TO THE MICROWAVE SINTERING OF YBCO

The possibility of heating and sintering a YBCO superconductor in a si ngle-mode cavity has been discussed by various authors and is thought to be related to the interaction between the electrical field and matt er. New results are presented here that show different behaviour of ma tter-radiation interactions for cylindrical samples aligned parallel t o the electrical field in the microwave cavity. Only bars smaller than the width of the cavity can be heated in their central zone in spite of a uniform distribution of the electrical field around the sample. T he limited heated zone and the discrepancy between the temperature of this zone versus the applied electrical field show that the law P = KE (a)2 does not describe the real heating process, suggesting that the e lectrical field is not the only factor that governs the heating of YBC O