Static Fields

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2. What are the sources of static electric fields?

Source: National Weather
Service, Albuquerque

Static electric fields of screens
Source:WHO

• In the atmosphere, static electric fields (also referred to as electrostatic fields) occur naturally, in fair weather, but especially under thunderclouds.
  
  A charge imbalance within the clouds or between a thundercloud and the ground generates fields that can result in electrical transfers which are visible as lightning (see illustration).
• Friction can also separate positive and negative charges and generate strong static fields. In daily life we may experience sparks or rising hair as a result of friction for example fom walking on a carpet.
• The use of direct current (DC) is another source of static electric fields. This is for example the case of rail systems using DC that can generate fields inside the train.
• Televisions and computer screens with cathode ray tubes1 can also generate electrostatic fields. These fields become visible, for instance, when screens attract dust.

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