Particle-in-cell simulation study of a 0.42 THz second-harmonic gyrotron oscillator Minghong Wang, Liming Zhang, Xianzhu Meng and Pukun Liu Eur. Phys. J. Appl. Phys., 63 1 (2013) 10902 Published online: 05 July 2013 DOI: 10.1051/epjap/2013120347