Collisional effects on the transient response of a cylindrical electrostatic probe

The low-frequency response characteristics of an electron-attracting cylindrical probe operating in the transition regime are presented. The analysis is applicable for probes of arbitrary ratios of radius to Debye length operating in plasmas where the collisional effects result from electron-neutral interactions. Equations which relate the probe current fluctuations to fluctuations in the plasma properties are presented with the intent of providing an explicit formulation for data interpretation. Conditions are also defined which must be satisfied if the intensity of the electron density fluctuations are to be determined directly from probe current measurements. In addition, qualitative results are presented which describe the probe transient response when collisional effects result from electron-ion interactions.