50.	PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES
51.	Physics of gases
51.10.+y	Kinetic and transport theory of gases (see also 05.20.Dd Kinetic theory in classical statistical mechanics)
51.20.+d	Viscosity, diffusion, and thermal conductivity
51.30.+i	Thermodynamic properties, equations of state (see also 05.70.Ce Thermodynamic functions and equations of state in thermodynamics)
51.35.+a	Mechanical properties; compressibility
51.40.+p	Acoustical properties (see also 43.28.-g Aeroacoustics and atmospheric sound in acoustics appendix; for ultrasonic relaxation in gases, see 43.35.Fj-in acoustics appendix)
51.50.+v	Electrical properties (ionization, breakdown, electron and ion mobility, etc.) (see also 52.80.-s Electric discharges in physics of plasmas)
51.60.+a	Magnetic properties
51.70.+f	Optical and dielectric properties
... ... ...	Sorption, see 68.43.-h in surfaces and interfaces, thin films and low-dimensional structures
... ... ...	Gas sensors and detectors, see 07.07.Df
51.90.+r	Other topics in the physics of gases (restricted to new topics in section 51)
52.	Physics of plasmas and electric discharges (for astrophysical plasmas, see 95.30.Qd; for physics of the ionosphere and magnetosphere, see 94.20.-y and 94.30.-d respectively)
52.20.-j	Elementary processes in plasmas
52.20.Dq	Particle orbits
52.20.Fs	Electron collisions
52.20.Hv	Atomic, molecular, ion, and heavy-particle collisions
52.25.-b	Plasma properties (for chemical reactions in plasma, see 82.33.Xj)
52.25.Dg	Plasma kinetic equations
52.25.Fi	Transport properties
52.25.Gj	Fluctuation and chaos phenomena (for plasma turbulence, see 52.35.Ra; see also 05.45.-a Nonlinear dynamics and nonlinear dynamical systems)
52.25.Jm	Ionization of plasmas
52.25.Kn	Thermodynamics of plasmas
52.25.Mq	Dielectric properties
52.25.Os	Emission, absorption, and scattering of electromagnetic radiation
52.25.Tx	Emission, absorption, and scattering of particles
52.25.Vy	Impurities in plasmas
52.25.Xz	Magnetized plasmas
52.25.Ya	Neutrals in plasmas
52.27.-h	Basic studies of specific kinds of plasmas
52.27.Aj	Single-component, electron-positive-ion plasmas
52.27.Cm	Multicomponent and negative-ion plasmas
52.27.Ep	Electron-positron plasmas
52.27.Gr	Strongly-coupled plasmas
52.27.Jt	Nonneutral plasmas
52.27.Lw	Dusty or complex plasmas; plasma crystals
52.27.Ny	Relativistic plasmas
52.30.-q	Plasma dynamics and flow
52.30.Cv	Magnetohydrodynamics (including electron magnetohydrodynamics) (see also 47.65.+a in fluid dynamics; for MHD generators, see 52.75.Fk)
52.30.Ex	Two-fluid and multi-fluid plasmas
52.30.Gz	Gyrokinetics
52.35.-g	Waves, oscillations, and instabilities in plasmas and intense beams
52.35.Bj	Magnetohydrodynamic waves (e.g., Alfven waves)
52.35.Dm	Sound waves
52.35.Fp	Electrostatic waves and oscillations (e.g., ion-acoustic waves)
52.35.Hr	Electromagnetic waves (e.g., electron-cyclotron, Whistler, Bernstein, upper hybrid, lower hybrid)
52.35.Kt	Drift waves
52.35.Lv	Other linear waves
52.35.Mw	Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)
52.35.Py	Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Qz	Microinstabilities (ion-acoustic, two-stream, loss-cone, beam-plasma, drift, ion- or electron-cyclotron, etc.)
52.35.Ra	Plasma turbulence
52.35.Sb	Solitons; BGK modes
52.35.Tc	Shock waves and discontinuities
52.35.Vd	Magnetic reconnection
52.35.We	Plasma vorticity
52.38.-r	Laser-plasma interactions (for plasma production and heating by laser beams, see 52.50.Jm)
52.38.Bv	Rayleigh scattering; stimulated Brillouin and Raman scattering
52.38.Dx	Laser light absorption in plasmas (collisional, parametric, etc.)
52.38.Fz	Laser-induced magnetic fields in plasmas
52.38.Hb	Self-focussing, channeling, and filamentation in plasmas
52.38.Kd	Laser-plasma acceleration of electrons and ions (see also 41.75.Jv Laser-driven acceleration in electromagnetism; electron and ion optics)
52.38.Mf	Laser ablation (see also 79.20.Ds, Laser-beam impact phenomena)
52.38.Ph	X-ray, gamma-ray and particle generation
52.40.-w	Plasma interactions (nonlaser)
52.40.Db	Electromagnetic (nonlaser) radiation interactions with plasma
52.40.Fd	Plasma interactions with antennas; plasma-filled waveguides
52.40.Hf	Plasma-material interactions; boundary layer effects
52.40.Kh	Plasma sheaths
52.40.Mj	Particle beam interactions in plasmas
52.50.-b	Plasma production and heating (for Electric discharges, see 52.80.-s)
52.50.Dg	Plasma sources
52.50.Gj	Plasma heating by particle beams
52.50.Jm	Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.50.Lp	Plasma production and heating by shock waves and compression
52.50.Nr	Plasma heating by DC fields; ohmic heating, arcs
52.50.Qt	Plasma heating by radio-frequency fields; ICR, ICP, helicons
52.50.Sw	Plasma heating by microwaves; ECR, LH, collisional heating
52.55.-s	Magnetic confinement and equilibrium (see also 28.52.-s Fusion reactors)
52.55.Dy	General theory and basic studies of plasma lifetime, particle and heat loss, energy balance, field structure, etc.
52.55.Ez	Theta pinch
52.55.Fa	Tokamaks, spherical tokamaks
52.55.Hc	Stellarators, torsatrons, heliacs, bumpy tori, and other toroidal confinement devices
52.55.Ip	Spheromaks
52.55.Jd	Magnetic mirrors, gas dynamic traps
52.55.Lf	Field-reversed configurations, rotamaks, astrons, ion rings, magnetized target fusion, and cusps
52.55.Pi	Fusion products effects (e.g., alpha-particles, etc.), fast particle effects
52.55.Rk	Power exhaust; divertors
52.55.Tn	Ideal and resistive MHD modes; kinetic modes
52.55.Wq	Current drive; helicity injection
52.57.-z	Laser inertial confinement
52.57.Bc	Target design and fabrication
52.57.Fg	Implosion symmetry and hydrodynamic instability (Rayleigh-Taylor, Richtmyer-Meshkov, imprint, etc.)
52.57.Kk	Fast ignition of compressed fusion fuels
52.58.-c	Other confinement methods
52.58.Ei	Light-ion inertial confinement
52.58.Hm	Heavy-ion inertial confinement
52.58.Lq	Z-pinches, plasma focus and other pinch devices
52.58.Qv	Electrostatic and high-frequency confinement
52.59.-f	Intense particle beams and radiation sources (see also 29.25.-t and 29.27.-a in instrumentation for particle and nuclear physics)
52.59.Bi	Grid- and ion-diode-accelerated beams
52.59.Dk	Magneto-plasma accelerated plasmas
52.59.Fn	Multistage accelerated heavy-ion beams
52.59.Hq	Dense plasma focus
52.59.Mv	High-voltage diodes (for high-current and high-voltage technology, see 84.70.+p)
52.59.Px	Hard X-ray sources
52.59.Qy	Wire array Z-pinches
52.59.Rz	Free-electron devices (for free-electron lasers, see 41.60.Cr)
52.59.Sa	Space-charge-dominated beams
52.59.Tb	Moderate-intensity beams
52.59.Wd	Emittance-dominated beams
52.59.Ye	Plasma devices for generation of coherent radiation
52.65.-y	Plasma simulation
52.65.Cc	Particle orbit and trajectory
52.65.Ff	Fokker-Planck and Vlasov equation
52.65.Kj	Magnetohydrodynamic and fluid equation
52.65.Pp	Monte Carlo methods
52.65.Rr	Particle-in-cell method
52.65.Tt	Gyrofluid and gyrokinetic simulations
52.65.Vv	Perturbative methods
52.65.Ww	Hybrid methods
52.65.Yy	Molecular dynamics methods
52.70.-m	Plasma diagnostic techniques and instrumentation
52.70.Ds	Electric and magnetic measurements
52.70.Gw	Radio-frequency and microwave measurements
52.70.Kz	Optical (ultraviolet, visible, infrared) measurements
52.70.La	X-ray and gamma-ray measurements
52.70.Nc	Particle measurements
52.72.+v	Laboratory studies of space- and astrophysical-plasma processes (see also 95.30.Qd in fundamental aspects of astrophysics and 94.20.-y and 94.30.-d in aeronomy and magnetospheric physics)
52.75.-d	Plasma devices (for ion sources, see 29.25.Lg, Ni; for plasma sources, see 52.50.Dg)
52.75.Di	Ion and plasma propulsion
52.75.Fk	Magnetohydrodynamic generators and thermionic convertors; plasma diodes (see also 84.60.Lw, Ny in direct-energy conversion and storage)
52.75.Hn	Plasma torches
52.75.Kq	Plasma switches (e.g., spark gaps)
52.75.Xx	Thermionic and filament-based sources (e.g., Q machines, double- and triple-plasma devices, etc.)
52.77.-j	Plasma applications
52.77.Bn	Etching and cleaning (see also 81.65.Cf Surface cleaning, etching, patterning in surface treatments)
52.77.Dq	Plasma-based ion implantation and deposition (see also 81.15.Jj Ion and electron beam-assisted deposition)
52.77.Fv	High-pressure, high-current plasmas (plasma spray, arc welding, etc.) (see also 81.15.Rs Spray coating techniques)
... ... ...	Chemical synthesis; combustion synthesis, see 81.20.Ka
52.80.-s	Electric discharges (see also 51.50.+v Electrical properties of gases; for plasma reactions including flowing afterglow and electric discharges, see 82.33.Xj in physical chemistry and chemical physics)
52.80.Dy	Low-field and Townsend discharges
52.80.Hc	Glow; corona
52.80.Mg	Arcs; sparks; lightning; atmospheric electricity (see also 92.60.Pw in hydrospheric and atomospheric geophysics)
52.80.Pi	High-frequency and RF discharges
52.80.Qj	Explosions; exploding wires
52.80.Sm	Magnetoactive discharges (e.g., Penning discharges)
52.80.Tn	Other gas discharges
52.80.Vp	Discharge in vacuum
52.80.Wq	Discharge in liquids and solids (for electric breakdown in liquids, see 77.22.Jp)
52.80.Yr	Discharges for spectral sources (including inductively coupled plasma)
52.90.+z	Other topics in physics of plasmas and electric discharges (restricted to new topics in section 52)