Application of integral equation theory to analyze stability of electric field in multimode microwave heating cavityZhengming Tang, Tao Hong, Fangyuan Chen, Huacheng Zhu and Kama HuangEur. Phys. J. Appl. Phys., 80 1 (2017) 10902DOI: https://doi.org/10.1051/epjap/2017170126