50.	PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES
51.	Physics of gases
51.10.+y	Kinetic and transport theory of gases
51.20.+d	Viscosity, diffusion, and thermal conductivity of gases
51.30.+i	Thermodynamic properties of gases, equations of state
51.35.+a	Mechanical properties of gases; compressibility
51.40.+p	Acoustical properties of gases
51.50.+v	Electrical properties of gases including ionization, breakdown, electron and ion mobility, etc
51.60.+a	Magnetic properties of gases
51.70.+f	Optical and dielectric properties of gases
51.90.+r	Other topics in the physics of gases (restricted to new topics in section 51)
52.	Physics of plasmas and electric discharges
52.20.-j	Elementary processes in plasma
52.20.Dq	Particle orbits in plasma
52.20.Fs	Electron collisions in plasma
52.20.Hv	Atomic, molecular, ion, and heavy-particle collisions in plasma
52.25.-b	Plasma properties
52.25.Dg	Plasma kinetic equations
52.25.Fi	Plasma transport properties
52.25.Gj	Plasma fluctuation and chaos phenomena
52.25.Jm	Ionization of plasmas
52.25.Kn	Thermodynamics of plasmas
52.25.Mq	Plasma dielectric properties
52.25.Os	Emission, absorption, and scattering of electromagnetic radiation from plasmas
52.25.Tx	Emission, absorption, and scattering of particles in plasma
52.25.Vy	Impurities in plasmas
52.25.Xz	Magnetized plasmas
52.25.Ya	Neutrals in plasma
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	Plasma magnetohydrodynamics including electron magnetohydrodynamics
52.30.Ex	Two-fluid and multi-fluid plasmas
52.30.Gz	Gyrokinetics in plasmas
52.35.-g	Waves, oscillations, and instabilities in plasmas and intense beams
52.35.Bj	Plasma magnetohydrodynamic waves e.g. Alfven waves
52.35.Dm	Plasma sound waves
52.35.Fp	Plasma electrostatic waves and oscillations e.g., ion-acoustic waves
52.35.Hr	Plasma electromagnetic waves electron-cyclotron, Whistler, Bernstein, upper hybrid, lower hybrid waves
52.35.Kt	Plasma drift waves
52.35.Lv	Other plasma linear waves
52.35.Mw	Nonlinear phenomena: plasma waves, wave propagation and other interactions including parametric effects, mode coupling, ponderomotive effects, etc
52.35.Py	Plasma macroinstabilities (hydromagnetic) e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor instabilities, etc
52.35.Qz	Plasma microinstabilities including ion-acoustic, two-stream, loss-cone, beam-plasma, drift, ion- or electron-cyclotron instabilities, etc
52.35.Ra	Plasma turbulence
52.35.Sb	Plasma solitons; BGK modes
52.35.Tc	Shock waves and discontinuities in plasma
52.35.Vd	Magnetic reconnection in plasmas
52.35.We	Plasma vorticity
52.38.-r	Laser-plasma interactions
52.38.Bv	Rayleigh scattering; stimulated Brillouin and Raman scattering in plasmas
52.38.Dx	Laser light absorption in plasmas including 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
52.38.Mf	Laser ablation
52.38.Ph	X-ray, gamma-ray and particle generation by lasers in plasmas
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
52.50.Dg	Plasma sources
52.50.Gj	Plasma heating by particle beams
52.50.Jm	Plasma production and heating by laser beams including 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 including ICR, ICP, helicons
52.50.Sw	Plasma heating by microwaves including ECR, LH, collisional heating
52.55.-s	Magnetic plasma confinement and equilibrium
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
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 and fast particle effects in plasma e.g. alpha-particles, etc
52.55.Rk	Power exhaust; Divertors in magnetic plasma confinement
52.55.Tn	Ideal and resistive plasma MHD modes; kinetic modes
52.55.Wq	Current drive; helicity injection in magnetic plasma confinement
52.57.-z	Laser inertial confinement
52.57.Bc	Target design and fabrication for laser ICF
52.57.Fg	Implosion symmetry and hydrodynamic instability for laser ICF including Rayleigh-Taylor, Richtmyer-Meshkov, imprint, etc
52.57.Kk	Fast laser ignition of compressed fusion fuels
52.58.-c	Other plasma confinement methods
52.58.Ei	Light-ion inertial plasma confinement
52.58.Hm	Heavy-ion inertial plasma confinement
52.58.Lq	Z-pinches, plasma focus and other pinch devices
52.58.Qv	Electrostatic, high frequency, and other nonmagnetic plasma confinement
52.59.-f	Intense particle beams and radiation sources in plasmas
52.59.Bi	Grid- and ion-diode-accelerated beams in plasmas
52.59.Dk	Magneto-plasma accelerated plasmas
52.59.Fn	Multistage accelerated heavy-ion beams in plasmas
52.59.Hq	Dense plasma focus
52.59.Mv	High-voltage plasma diodes
52.59.Px	Plasma hard X-ray sources
52.59.Qy	Wire array Z-pinches
52.59.Rz	Free-electron devices in plasmas
52.59.Sa	Space-charge-dominated particle beams in plasmas
52.59.Tb	Moderate-intensity particle beams in plasmas
52.59.Wd	Emittance-dominated particle beams in plasmas
52.59.Ye	Plasma devices for generation of coherent radiation
52.65.-y	Plasma simulation
52.65.Cc	Particle orbit and trajectory (plasma simulation)
52.65.Ff	Fokker-Planck and Vlasov equation (plasma simulation)
52.65.Kj	Magnetohydrodynamic and fluid equation (plasma simulation)
52.65.Pp	Monte Carlo methods (plasma simulation)
52.65.Rr	Particle-in-cell method (plasma simulation)
52.65.Tt	Gyrofluid and gyrokinetic plasma simulations
52.65.Vv	Perturbative methods (plasma simulation)
52.65.Ww	Hybrid methods (plasma simulation)
52.65.Yy	Molecular dynamics methods (plasma simulation)
52.70.-m	Plasma diagnostic techniques and instrumentation
52.70.Ds	Electric and magnetic plasma diagnostic measurements
52.70.Gw	Radio-frequency and microwave plasma diagnostic measurements
52.70.Kz	Optical (ultraviolet, visible, infrared) plasma diagnostic measurements
52.70.La	X-ray and -ray plasma diagnostic measurements
52.70.Nc	Particle plasma diagnostic measurements
52.72.+v	Laboratory studies of space- and astrophysical-plasma processes
52.75.-d	Plasma devices
52.75.Di	Ion and plasma propulsion
52.75.Fk	Magnetohydrodynamic generators and thermionic convertors; plasma diodes
52.75.Hn	Plasma torches
52.75.Kq	Plasma switches e.g., spark gaps
52.75.Xx	Thermionic and filament based plasma sources e.g. Q machines, double- and triple-plasma devices, etc
52.77.-j	Plasma applications
52.77.Bn	Etching and cleaning in plasmas
52.77.Dq	Plasma-based ion implantation and deposition
52.77.Fv	Applications of high-pressure, high-current plasmas including plasma spray, arc welding, etc
52.80.-s	Electric discharges
52.80.Dy	Low-field and Townsend discharges
52.80.Hc	Glow; corona discharges
52.80.Mg	Arcs; sparks; lightning; atmospheric electricity
52.80.Pi	High-frequency and RF discharges
52.80.Qj	Explosions; exploding wires (electrical discharges)
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
52.80.Yr	Discharges for spectral sources
52.90.+z	Other topics in physics of plasmas and electric discharges (restricted to new topics in section 52)