We report the first experimental identification of the new wave branch at electron cyclotron frequency produced by the injection of a frequency-matched intense pump wave in magnetized plasma [A. G. Litvak and M. D. Tokman, Phys. Rev. Lett. 88, 095003 (2002); G. Shvets and J. S. Wurtele, Phys. Rev. Lett. 89, 115003 (2002)], which is a classical phenomenon analogous to electromagnetically induced transparency (EIT) in quantum systems. By using a frequency-sweep interferometer, we directly detected the dispersion relation of the plasma EIT branch for propagation parallel to the background magnetic field. The bandwidth of the EIT window was correlated with the pump-wave electric field and was found to agree with the theoretical prediction.

This paper presents a newly developed lithium plasma emitter, which can provide quiescent and low-temperature collisionless conditions for magnetized plasma experiments. This plasma emitter generates thermal emissions of lithium ions and electrons to produce a lithium plasma. Lithium type beta-eucryptite and lanthanum-hexaboride (LaB(6)) powders were mixed and directly heated with a tungsten heater to synthesize ion and electron emissions. As a result, a plasma with a diameter of ~15 cm was obtained in a magnetic mirror configuration. The typical range of electron density was 10(12)-10(13) m(-3) and that of electron temperature was 0.1-0.8 eV with the emitter operation temperature of about 1500 K. The amplitude fluctuations for the plasma density were lower than 1%.