1928-1929

Plasma oscillation

• In the ultraviolet region, the dielectric function
• of a free electron gas is unstable,
• so that its charge density
• can oscillate at the electron plasma frequency.
• These oscillations occur in any plasma—
• in vacuum tubes, in the ionosphere,
• and across the heliosphere in solar wind—
• started by accidental variations of electron density.

Langmuir waves

• In the Van Allen belts, Langmuir waves
• act like an orchestral conductor,
• modulating as well as modulated by whistler-mode chorus waves.
• *
• In the hot plasmas of fusion experiments,
• temperature gradients cause Langmuir waves
• subject to Landau damping and Thomson scattering.
• *
• Electron beams accelerated by solar flares and nanoflares
• in the solar corona and interplanetary medium
• cause radio bursts from cyclically collapsing Langmuir waves.

Instabilities

• Instabilities
• attract emissions.
• No, they don’t
• attract emissions.
• You may know
• what I’m about.