Home Wikituition Browse all terms Categories
Random term

Plasma Physics

60 terms · page 1 of 3


A–Z
All A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Filtering by: Plasma Physics Clear all
Plasma Physics

Alfvén Wave

A fundamental magnetohydrodynamic (MHD) wave in which ions in a magnetized plasma oscillate in response to magnetic field line tension.

v_A = B / √(μ₀ ρ_plasma) m/s (Alfvén Velocity)
Plasma Physics

Bohm Sheath Criterion

A fundamental boundary condition stating that positive ions entering a non-neutral plasma sheath must enter with a velocity at or exceeding…

v_ion ≥ c_s = √(k_B T_e / m_i) (at Sheath Entrance) m/s (Ion Acoustic Sound Speed c_s)
Plasma Physics

Bootstrap Current

A self-generated toroidal electric current in a tokamak plasma driven by trapped particle banana orbits in steep pressure gradients.

I_bootstrap ∝ √ε (k_B / B_poloidal) (dn / dr) MA (Plasma Current Fraction)
Plasma Physics

Bremsstrahlung Radiation in Plasma

Continuous electromagnetic radiation emitted when free plasma electrons undergo deceleration scattering off positive ions.

P_brems ∝ Z_eff n_e² √T_e W/m³ (Radiated Power Density)
Plasma Physics

Burning Plasma & Alpha Heating

The state of a fusion plasma where thermal heating from 3.5 MeV alpha particles produced in Deuterium-Tritium fusion reactions becomes the…

P_alpha / P_heating ≥ 50% (Burning Plasma Condition Q ≥ 10) MW (Alpha Particle Heating Power)
Plasma Physics

Cold Atmospheric Pressure Plasma Jet

A non-thermal plasma discharge generated at ambient atmospheric pressure where heavy ions remain near room temperature while free electrons…

T_gas ≈ 300 K (Room Temp), T_electron ~ 10,000–50,000 K K (Gas Temperature ~300 K)
Plasma Physics

Coulomb Logarithm

The natural logarithm of the ratio of maximum to minimum impact parameters in small-angle Coulomb collision integrals.

ln Λ = ln(r_max / r_min) = ln(λ_D / b_min) ≈ 10–20 Dimensionless Parameter (ln Λ)
Plasma Physics

Cyclotron & Synchrotron Emission

Electromagnetic radiation emitted by charged particles undergoing gyromotion acceleration around magnetic field lines in a plasma.

P_rad = (2 e⁴ B² v_⊥²) / (3 m_e² c³) (Non-relativistic Cyclotron) W (Radiated Power)
Plasma Physics

Debye Length

The characteristic spatial scale over which mobile charge carriers in a plasma screen out localized electrostatic potentials.

λ_D = √(ε₀ k_B T_e / (n_e e²)) m (Meters)
Plasma Physics

Dense Plasma Focus

A pulsed plasma device that uses electromagnetic forces to accelerate and pinch a plasma column into a short-lived, high-density hot spot.

E_k ~ 10–100 kJ (Electromagnetic Acceleration and Pinch) kJ (Capacitor Energy) & Short Pulses (ns)
Plasma Physics

Divertor

A component in a fusion tokamak that uses magnetic null points (X-points) to extract helium ash and heat exhaust from the plasma edge.

Magnetic X-point Separatrix Boundary Geometry MW/m² (Heat Flux Capacity)
Plasma Physics

Dusty Plasma

A complex plasma containing solid nanometer-to-micrometer scale dust grains that collect high negative charges from surrounding plasma…

Q_dust ~ - 10³ e to - 10⁵ e (Charged Micron Dust Grains) μm (Dust Size) & Charged State
Plasma Physics

Edge Localized Modes (ELMs)

Periodic magnetohydrodynamic bursts occurring at the boundary edge pedestal of H-mode tokamak plasmas, expelling heat and particles toward…

Magnetohydrodynamic Peeling-Ballooning Boundary Instability MJ (Energy Loss Pulse per ELM)
Plasma Physics

Field-Reversed Configuration (FRC)

A high-beta compact toroid magnetic confinement concept where a closed-poloidal-field plasma torus is sustained inside a simple linear…

Average Beta ⟨β⟩ ≈ 1 (High-Beta Compact Toroid) Dimensionless High Beta ⟨β⟩ ~ 0.9
Plasma Physics

Fokker-Planck Equation for Plasmas

The kinetic equation describing the time evolution of a plasma velocity distribution function subject to small-angle Coulomb collisions.

(∂f / ∂t)_coll = -∇_v · (A f) + ½ ∇_v ∇_v : (B f) Kinetic Collision Operator
Plasma Physics

Gyroradius & Cyclotron Frequency

The helical orbital radius (Larmor radius r_L) and angular frequency (cyclotron frequency ω_c) of a charged particle orbiting a magnetic…

r_L = (m v_⊥) / (|q| B), ω_c = (|q| B) / m m (Larmor Radius) & rad/s (Cyclotron Frequency)
Plasma Physics

H-mode Confinement

High-confinement operating regime in tokamaks characterized by a steep edge pressure barrier (pedestal) and doubled energy confinement time.

Energy Confinement Time τ_E(H-mode) ≈ 2 × τ_E(L-mode) s (Energy Confinement Time τ_E)
Plasma Physics

Hall Effect Thruster

A electric space propulsion plasma engine that accelerates ions across an electrostatic potential drop using trapped electrons in an…

F_thrust = ṁ v_exhaust, v_ex = √(2 e V_acc / m_ion) N or mN (Thrust) & s (Specific Impulse ~1500–3000 s)
Plasma Physics

Inertial Confinement Fusion

A fusion energy approach that uses intense laser or ion beam pulses to rapidly compress and heat a millimeter-scale fuel capsule to fusion…

ρ R ≥ 1 g/cm² (Compressed Areal Density) g/cm² (Areal Density) & Mbar (Implosion Pressure)
Plasma Physics

Interchange & Flute Instabilities

A magnetohydrodynamic (MHD) instability where high-pressure plasma and low-density magnetic fields interchange spatial positions in regions…

Bad Curvature Condition: (∇P) · (∇B) > 0 MHD Flute Mode Instability
Plasma Physics

Ionization Energy

The minimum energy required to detach an electron from a neutral atom or ion, initiating gas-to-plasma phase transformation.

E_ion = h ν - K_e (Saha Ionization Equation) eV (Electron-Volts)
Plasma Physics

Kink & Sausage Instabilities

Ideal magnetohydrodynamic (MHD) macro-instabilities occurring in current-carrying pinched plasma columns.

m = 0 (Sausage Mode), m = 1 (Kink Mode) MHD Instability Modes
Plasma Physics

Landau Damping

The collisionless damping of electrostatic plasma waves caused by energy exchange between wave electric fields and particles moving near…

γ_L = (π ω_pe³ / (2 k²)) (df₀ / dv)|_(v = ω/k) s⁻¹ (Damping Rate γ)
Plasma Physics

Langmuir Probe

A diagnostic electrode inserted directly into a plasma to measure local electron temperature, plasma density, and floating potential from…

I(V) = I_i,sat - I_e,sat exp(e (V - V_plasma) / (k_B T_e)) A (Measured Current) & V (Bias Voltage)