Elektronivärähdykset

Elektronivärähdykset, known in English as electron oscillations or plasma oscillations, are collective phenomena occurring in plasmas where electrons are displaced from their equilibrium positions. These oscillations arise from the restoring force exerted by the stationary ions on the displaced electron cloud. When electrons are pushed away from their equilibrium by some disturbance, the positively charged ions in the plasma create an electric field that pulls the electrons back. This results in an oscillatory motion of the electron gas around the fixed ion background.

The frequency of these oscillations, known as the electron plasma frequency, is a fundamental property of a plasma and depends on the electron number density and electron charge and mass. It is a high frequency, typically in the radio wave or microwave range, and is independent of the ion mass and temperature. Electron oscillations are a key characteristic of plasmas and play a significant role in various plasma phenomena, including wave propagation, instabilities, and energy transfer. They can be excited by external sources or by internal plasma processes. Understanding electron oscillations is crucial for diagnosing plasma properties and for developing applications involving plasmas.