Permanently Magnetized Ferrite Antenna Windows for Improving Electromagnetic Wave Transmission Through a Plasma

摘要

A longitudinal magnetic field (Bsubz) can be employed to increase the transmission through a plasma of a righthand polarized electromagnetic (EM) wave at below the natural plasma frequency. The Bsubz field can be produced by permanently magnetized ferrite material in the form of a thick sheet placed as a window in front of the radiator and directly adjacent to the plasma. The crucial point is that it has been shown by test that high-frequency EM waves can be transmitted with only reasonable attenuation through a thick sheet of ferrite which is producing a Bsubz > 1500 gauss longitudinal field at the sheet surface. Further, due to its rotational field-displacement properties, there exists the possibility that the magnetized ferrite sheet serving as the antenna window may be so constructed as to be simultaneously an isolator and thereby reduce the changes in load impedance seen by the radiator with varying plasma sheath conditions. (Author)