A passive probe for electrostatic charge density measurements

A probe has been developed to detect space charge density in flow streams. The probe not only measures the average space charge at a point, but also very small amplitude fluctuations up to 1 kHz. This electrostatic probe has a simple design and consists of a miniature central electrode and a hollow aerodynamically shaped shielding electrode for minimal flow disturbance. The high‐frequency response of the probe and its simple design would make it desirable in many applications. Results of tests in a charged turbulent free jet flow of kerosene indicating the probe capabilities are presented.