Search

A pole mounted 'field mill' type electrostatic fieldmeter provides a simple and practical way for measurement, and for long term continuous monitoring, of ground level atmospheric electric fields. The paper describes a number of studies of this measurement method. These show how atmospheric electric field values are derived from the response of the fieldmeter when earth bonded and its height above ground level. The response of the fieldmeter is calibrated via the linear variation of its response to voltage applied during the set up procedure. The studies confirm a linearity of fieldmeter response with height above ground. [ABSTRACT FROM AUTHOR]

We report experimental observations of the controlled deformation of a dielectric liquid jet subjected to a local high-voltage electrostatic field in the direction normal to the jet. The jet deforms to the shape of an elliptic cylinder upon application of a normal electrostatic field. As the applied electric field strength is increased, the elliptic cylindrical jet deforms permanently into a flat sheet, and eventually breaksup into droplets. We interpret this observation--the stretch of the jet is in the normal direction to the applied electric field--qualitatively using the Taylor-Melcher leaky dielectric theory, and develop a simple scaling model that predicts the critical electric field strength for the jet-to-sheet transition. Our model shows a good agreement with experimental results, and has a form that is consistent with the classical drop deformation criterion in the Taylor-Melcher theory. Finally, we statistically analyze the resultant droplets from sheet breakup, and find that increasing the applied electric field strength improves droplet uniformity and reduces droplet size. [ABSTRACT FROM AUTHOR]

The response of field mill type electrostatic fieldmeters to alternating electric fields is limited by the chopping frequency. Measurements reported here show that alternating frequencies at the chopping frequency, and related harmonics, can create confusing low frequency outputs. Hence care is needed for interpreting observations where such alternating electric fields may be present. [ABSTRACT FROM AUTHOR]