
The process of increasing the thermal energy of plasma, often through magnetic energy release.Plasma heating refers to the various processes that increase the thermal energy of a plasma — a hot, ionized gas of charged particles. In astrophysical contexts, it explains why the solar corona is millions of degrees hotter than the Sun's surface, and why solar flares release enormous amounts of energy. In laboratory fusion devices, plasma heating is essential to reach the temperatures needed for nuclear fusion, but it also poses challenges because turbulent losses can cool the plasma faster than it is heated.
The puzzle of coronal heating was recognized in the 1930s, and magnetic reconnection was proposed as a mechanism by Ronald Giovanelli in 1946 and later developed by Peter Sweet and Eugene Parker in the 1950s.
One major mechanism is magnetic reconnection, where magnetic field lines break and reconnect, converting magnetic energy into kinetic and thermal energy of the plasma. Another is wave heating: electromagnetic waves (like Alfvén waves) propagate through the plasma and are absorbed, transferring their energy to particles. Turbulence also plays a role — chaotic fluid motions can cascade energy from large scales to small scales, where it is dissipated as heat. In fusion devices, neutral beam injection and radio-frequency waves are used to heat the plasma externally.
Plasma heating is critical for magnetic confinement fusion experiments like ITER, where it is used to bring deuterium-tritium fuel to temperatures above 150 million degrees Celsius, and for understanding space weather that affects satellites and power grids.
In the solar corona, the heating is so efficient that the temperature reaches about 1-3 million degrees Celsius, yet the density is so low that a spacecraft passing through it would not melt — it would just feel a gentle warmth.





















