Collision absorption and resonance absorption of electromagnetic waves by array plasma

This article described the experiment on the absorption of 1-18GHz electromagnetic (EM) waves by array plasma which was produced by many standard commercial fluorescent lamps placed directly against each other in two rows. Weak reflection and strong absorption were observed. Predictive peak electron density and collision frequency were discussed and compared with measurement. The results indicated that the single-pass collision absorption reached the maximum of about 10dB, when incident frequency approached to collision frequency. Resonance absorption took place in the case of plasma properties varying along electric field of incident wave, when the incident frequency approached to the peak plasma frequency.