First-principles calculations in plasma physics

Computational plasma models derived from fundamental laws such as electromagnetism and kinetic theory, rather than fitted empirical relations or phenomenological closures.

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Vlasov–Maxwell system: A kinetic description coupling charged-particle distribution functions to electromagnetic fields through the Vlasov and Maxwell equations. It gives collisionless plasma calculations a direct foundation in particle dynamics and electromagnetism.
Kinetic theory: A framework that describes matter through the statistical distributions and motions of its constituent particles. It underlies calculations that retain velocity-space structure absent from ordinary fluid models.
Magnetic reconnection: A process in which magnetic-field topology changes and magnetic energy is converted into particle energy. Kinetic calculations reveal how particle-scale physics enables rapid changes in magnetic connectivity.
Magnetohydrodynamics: A fluid theory of electrically conducting matter coupled to magnetic fields. Its fluid closure is efficient but suppresses much particle-scale kinetic behavior.
Particle-in-cell method: A computational method that advances representative charged particles while solving electromagnetic fields on a spatial grid. It numerically approximates kinetic plasma dynamics without prescribing fluid closure relations.
Plasma parameter: A measure of the number of particles within a plasma Debye sphere, indicating the strength of collective behavior. It helps establish when a continuum kinetic description is physically justified.
Collisionless shock: A shock structure in a plasma formed mainly through collective electromagnetic fields rather than binary collisions. Particle simulations resolve the mechanisms that create and heat collisionless shocks.
Two-fluid model: A plasma model that treats electrons and ions as separate interacting fluids. It retains some species differences while closing equations without full distribution functions.
Direct simulation Monte Carlo: A stochastic particle method that models collisions by sampling interactions among simulated particles. It supplies a first-principles route for dilute plasmas where collisions matter.
Debye length: The characteristic distance over which mobile charges screen an electric field in a plasma. It sets a fundamental spatial scale for resolving collective electrostatic effects.