Effect of Humidity on Charge Decay in Varying Atmospheric Gases

Zachary Cardenas, Ben Esser, Ivan Aponte, James Dickens, John Mankowski, Jacob Stephens, Donald Friesen, Crystal Nelson, Neil Koone, David Hattz, Andreas Neuber

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Characterization of surface charge decay for varying materials-PTFE, Acrylic, and metals-of 100 mm diameter, radially symmetric bodies was performed. In a gaseous environment, charged materials will lose their charge depending on gas type, humidity, and other environmental factors. Eventually, the charge will be (1) neutralized by ions or electrons in the surrounding gas (2) distributed by conduction on the material surface or in its volume (3) or neutralized by ions or electrons in the material surface and volume. Metal and polymer samples are charged to a known potential in the tens of kilovolts range, and the decaying voltage is monitored with a non-contact probe until the potential reaches near zero. Humidity has an impact on both groups of materials. As a baseline, in air at 42% relative humidity in an enclosed chamber, a positive charge equivalent to 20 kV potential on a metal sphere of 50 mm radius decays to near zero within 25 minutes. In contrast, the same sphere negatively charged decays slightly faster within 20 minutes. Overall, the humidity has a significant effect on the charge decay time, such that an order of magnitude longer times (hours) are observed at low humidity. Effects of chamber size were also studied, drawing a connection to charge carriers in the air available for decay, with chambers of volume(s): 3.3 105 cm3 and 1.4 106 cm3, respectively.

Original languageEnglish
Title of host publication2021 IEEE Pulsed Power Conference, PPC 2021
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781665433471
StatePublished - 2021
Event2021 IEEE Pulsed Power Conference, PPC 2021 - Denver, United States
Duration: Dec 12 2021Dec 16 2021

Publication series

NameIEEE International Pulsed Power Conference
ISSN (Print)2158-4915
ISSN (Electronic)2158-4923


Conference2021 IEEE Pulsed Power Conference, PPC 2021
Country/TerritoryUnited States


  • Charge decay
  • charge carriers
  • dielectric surface charge


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