Comment on “Microwave attenuation of hydrogen plasma in carbon nanotubes” [J. Appl. Phys. 104, 124315 (2008)

Abstract

In a recent article, Babaei and Solari [J. Appl. Phys. 104, 124315 (2008)] studied the effects of the electron temperature, and the external static magnetic field on the attenuation (ATT) of the microwave in the hydrogen plasma embedded inside the carbon nanotubes (CNTs), which were grown by iron-catalyzed high-pressure disproportionation (HiPco). They showed that the position of ATT peak shifts significantly toward high frequency with increasing thermal frequency and in the presence of an external magnetic field in the Faraday configuration, for υc<20 GHz, the ATT coefficient increases with increasing cyclotron frequency, and for υc>20 GHz, the ATT level variations extremely increase, where υc is the cyclotron frequency. Here we derive the correct form of the microwave absorption coefficient of the magnetized hydrogen plasma embedded inside the CNTs and show that the absorption band moves from low to high frequencies when the magnetic field strength increases. Also, we show that the ATT of the microwave in the system is not sensitive to the thermal frequency.