Plasma density measurements by phase resolved cutoff

摘要

A method for precise measurement of absolute electron density in the plasma using plasmanfrequency is proposed. The phase difference between two antennas u0001radiating and detectingnantennasu0002 and its slow time modulation was used, instead of the transmittance used in previousncutoff probe, and a remarkable result is observed. This method can determine the absolute electronndensity precisely: It is not only in a good agreement with the previous method very closely butnalso is able to find the cutoff point clearly even in difficult conditions where there are ambiguitiesnto determine the cutoff point with previous method. © 2010 American Institute of Physics.