Real-time material´s response to high power microwave irradiation revealed by in-situ synchrotron radiation methods

The complexity of microwave heating stems to a large extent from the intrinsic complexity of the materials exposed to microwave irradiation. For simple ideal homogeneous material, its size, shape and orientation with respect to the electromagnetic field influence the microwave absorption properties at the macroscopic scale. Furthermore, a number of material parameters, namely the complex permittivity and permeability, electrical conductivity, density etc. additionally determine the efficiency of the energy transfer from the microwave field to the sample. These material parameters are inter-correlated and may change significantly as function of frequency and temperature. For an homogeneous solid, the material parameters are defined by scalar values, i.e. having the same value throughout the specimen volume.