Particle-in-cell simulation study of a 0.42 THz second-harmonic gyrotron oscillatorMinghong Wang, Liming Zhang, Xianzhu Meng and Pukun LiuEur. Phys. J. Appl. Phys., 63 1 (2013) 10902DOI: https://doi.org/10.1051/epjap/2013120347