Terahertz Radiation from Glow Discharge in Coaxial Resonator

Summary form only given. The orbitron in which a low pressure glow discharge is created between the center and outer conductor by applying tens of kilovolts across them is capable of generating Terahertz radiation. A typical discharge can be divided into a plasma region with equal electron and ion densities and an electron-rich (positive wire potential) sheath region. Electron orbital motion around the thin wire (typically about 10^-3 cm) is negative mass unstable and terahertz radiation can be generated (one watt was obtained in Alexeff et al. 1985). In comparison with the current popular source (micro watt) that uses table-top laser-driven high-speed photoconductors as transient current sources for radiating antennas, the compact (pen size) orbitron is far better in output power and efficiency. Particle simulation results will be given to elucidate the phvsical mechanism of radiation generation. Both circular and eccentric orbital electrons are considered. They all have strong growth rates while the latter is rich in harmonics and can reach Terahertz region.