Estimation of plasma parameters using radio-frequency resonance technique

Numerous workers have studied rf resonance probe under the condition nu (m) < < omega (ep), i.e. under collisionless condition, where fv. is angular c ollision frequency and w(ep) is angular plasma frequency. In the present pa per, the interaction of rf signal with a back diffusion type plasma has bee n studied without neglecting collision frequency. The problem has been disc ussed theoretically under this condition, and the derivation yields two exp ressions for which impedance is minimum. To verify the result experimentall y, a rectangular plasma chamber is designed and fabricated, where electron density can be changed without changing the discharging potential and vacuu m conditions. From the experiment two resonance peaks are obtained in the I -f(2) curve (I: current and f: applied frequency) corresponding to the two minimum impedance conditions., from which plasma parameters like electron d ensity, collision frequency and electron temperature have been estimated.