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Arc modeling at Sumy,Ukraine

Arc modeling at Sumy,Ukraine Speakers: Serhiy Mordyk (Institute of Applied Physics, National Academy of Sciences of the Ukraine). DC-spark breakdown. Laser—induced breakdown. RF breakdown. What kind of plasma is produced during a breakdown, how does it develop with time?.

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Arc modeling at Sumy,Ukraine

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  1. Arc modeling at Sumy,Ukraine Speakers: Serhiy Mordyk (Institute of Applied Physics, National Academy of Sciences of the Ukraine)

  2. DC-spark breakdown Laser—induced breakdown RF breakdown What kind of plasma is produced during a breakdown, how does it develop with time? It is necessary to know plasma parameters for arc modeling

  3. Optical spectra tell us: Compositions: elements & molecules (line positions) Ion temperatures of plasma (Doppler effect) Vibrational and rotational temperatures of plasma (line strengths and positions) Pressures (line widths: pressure broadening) Plasma density ( Stark broadening) Magnetic fields (Zeeman splitting) Mass spectra tell us: Compositions: elements & molecules Time-resolved dynamics of discharge Microwave interferometer tells us: Plasma density Plasma diagnostics

  4. Setup for measurement of plasma parameters

  5. Time-resolved laser mass spectrometer

  6. Optical spectrometer

  7. Optical spectrum of nitrogen Helicon discharge (IAP NASU) Determination of vibrational and rotational temperature is necessary for modeling of kinetic of plasma processes

  8. Hydrogen optical line Stark broadening • H Balmer beta (486,1 nm) • Plasma density Doppler effect • H Balmer alpha (656,3 nm) Ion temperatures of plasma

  9. DC-spark (data from Jan Koverman) Sample Cu 9(7)

  10. DC-spark (data from Jan Koverman) Sample Cu 9(7) Strong optical line Н2 (462.9 nm) Processing of optical spectra was carried out with the assistance of Dr. O.M. Buhay

  11. Mechanisms underlying RF breakdowns in high-gradient accelerating structures explosion (Power absorption, Joule law) evaporation (Cu, H, O, N …) + Power absorption ionization – discharge electron plasma formation and disassimilation ion

  12. PIC model Source codes at OOPIC (Berkeley Laboratory) http://langmuir.nuc.berkeley.edu/pub/codes/xoopic/ Initial parameters Vlasov–Boltzmann Equation The length of the space z = 0.00005 m The radius of the space r = 0.00001 m The simulation time step Δt = 0. 001 ns The electron temperature Te = 5 eV The ion temperature Ti = 1 eV Initial plasma density n = 1019 m-3 Pressure in chamber p = 0.000001 Torr DC voltage φ = - 12000 V Maxwell’s equations Charge density, current density

  13. Initial state of plasma cathode anode

  14. Electrons on the anode

  15. Ions CU on the cathode

  16. Ions CU on the cathode

  17. Fluid model Equations system of the two fluids hydrodynamics Poisson equations A Equation of motion C PLASMA

  18. Integration model Vlasov–BoltzmannEquation: Poisson’s equation where na is the density: Photoionization

  19. Thank you

  20. Conclusion It is necessary to know plasma parameters for arc modeling

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