A Thunderon® passive static eliminator uses high voltage on a material surface to break down or ionize air molecules. High voltage in proximity to sharp points causes the electric field to concentrate and become very intense at the points.
A charged surface will have an electric field emanating from it. In most situations, this electric field will be perpendicular to the surface, and uniform. However, if a sharp point is brought into the vicinity of the field, the field lines will concentrate at the end of the point, creating a small region of highly concentrated fields. The Thunderon® tape uses this phenomenon of field concentration in the vicinity of points as a means of generating ions for charge neutralization.
In situations where the point is sufficiently sharp, the value of the electric field at the point tip will be greater than the breakdown strength of air. This causes air molecules to ionize. However, this ionization process will only occur where the field is sufficiently STRONG, i.e., at the point tip. This process is called corona or partial breakdown. It is an intrinsically stable breakdown process.
Since the ions are also subjected to the electric field, ions of one polarity (opposite the charge polarity of the surface) will travel along the electric field lines to the surface, thereby neutralizing its electric field. The opposite polarity ions will travel through the passive device to ground. This process will continue until the field has been reduced to the point where ionization stops. The surface voltage at which this occurs is essentially the same as the residual voltage.
A key to the Thunderon® Tape's excellent performance is its pick spacing. Non-continuous pick spacing increases the field concentration at the filament tips. Continuous picks cause adjacent picks to shield one another, with the result being an increase in the threshold voltage of ionization.
The intermittent fill of the Thunderon® tape is an advantage in that the shielding caused by adjacent fiber is minimized. This results in much lower corona threshold voltage.