Ilmapurkaus

Ilmapurkaus, known in English as an air discharge or atmospheric discharge, refers to the electrical breakdown of air. This phenomenon occurs when the electric field in the air becomes strong enough to overcome the insulating properties of the air itself. The breakdown results in the flow of electric current, often accompanied by visible light and sound. Common examples of ilmapurkaus include lightning during thunderstorms and sparks.

The process begins with the ionization of air molecules, where electrons are stripped from atoms. These free electrons are then accelerated by the electric field, colliding with other molecules and creating more free electrons. This chain reaction, known as an avalanche, leads to a conductive channel through which a significant current can flow. The rapid heating of the air along this channel causes it to expand explosively, producing the characteristic thunder associated with lightning.

The voltage required for ilmapurkaus depends on factors such as air pressure, humidity, and the distance over which the electric field is applied. At sea level, under normal atmospheric conditions, a voltage of approximately 3 million volts per meter is needed to initiate a discharge. Industrial applications exploit ilmapurkaus for processes like welding and ozone generation. Understanding ilmapurkaus is also crucial for electrical engineering, particularly in designing systems that can withstand or prevent such discharges.