plasma

History

The word 'plasma' (from Greek 'molded') was proposed by American physicist Irving Langmuir in 1928 while studying electrical discharges in gases. But the phenomenon has long been known: lightning and St. Elmo's fire are plasma.

How it works

When strongly heated, collisions between atoms knock electrons out of their orbits. A mixture of charged particles forms that collectively responds to electric and magnetic fields — much like a flock of birds simultaneously changing direction.

History

The word 'plasma' (from Greek 'molded') was proposed by American physicist Irving Langmuir in 1928 while studying electrical discharges in gases. But the phenomenon has long been known: lightning and St. Elmo's fire are plasma.

How it works

When strongly heated, collisions between atoms knock electrons out of their orbits. A mixture of charged particles forms that collectively responds to electric and magnetic fields — much like a flock of birds simultaneously changing direction.

History

Although gas discharges were studied by Michael Faraday in the 19th century, the term 'plasma' was introduced by Irving Langmuir in 1928 while working with ionized gases in electron tubes. Langmuir noticed a similarity between the behavior of the multi-electron medium and living tissue and used the Greek word meaning 'form' or 'molding'. The development of plasma theory in the mid-20th century was stimulated by astrophysics and thermonuclear research; major contributions were made by James Clerk Maxwell (equations of electrodynamics) and Ludwig Boltzmann (statistical kinetics).

How it works

The plasma state is achieved when the thermal motion energy exceeds the binding energy of electrons in atoms. A mixture of charged particles arises, interacting via long-range Coulomb forces, leading to collective effects: Debye screening and plasma oscillations. In a magnetic field, plasma is frozen into field lines, which explains its structures in space. To describe plasma, Maxwell's equations are used in combination with equations of particle motion; in thermodynamic equilibrium, the particle distribution follows the Boltzmann distribution.

Open problems & fun facts

Controlled thermonuclear fusion: confining plasma with temperatures of hundreds of millions of degrees.; Turbulence in plasma: understanding the mechanisms of energy and particle transport.; The problem of solar corona heating: why the Sun's corona is hotter than its surface.

💡 In plasma, the phenomenon of 'magnetization' can occur, where electrons and ions gyrate around magnetic field lines at a specific frequency (cyclotron).