Experiments and analysis of wave absorption, reflection and scattering in plasmas

Summary form only given. Measurements and analysis of the absorption, reflection, and scattering of electromagnetic waves due to electron cyclotron resonance zones and the presence of scatterers in the plasma were carried out. The 12-cm-diameter by 2-m laboratory plasma was produced by a 2.45-GHz microwave source in a local mirror field, with wave measurements carried out in a larger mirror region. The plasma density that could be created was in the range of 5×10⁹ to 5×10¹¹/cm³ with electron temperatures in the 3-6-eV range and 0.5-2-kG magnetic fields. Wave absorption measurements of 25-50 dB due to the electron cyclotron resonance zone in the 1.5-3.0-GHz range were performed. A modulated homodyne detection system that isolates the backscatter from a single object in the plasma and suppresses the scattering from the walls. probes, and other background was constructed. This system was used to measure the shielding produced by the plasma, including the shielding by cyclotron resonance. The effect of collisional absorption for particular density profiles in weakly magnetized plasmas was analyzed to determine their effect on reflectivity. For collisional. low-magnetic-field plasma conditions comparable to those that can be obtained in the present experiments, the electromagnetic wave reflectivity was calculated using various Epstein profiles