Arc modeling at Sumy,Ukraine
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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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Arc modeling at sumy ukraine

Arc modeling at Sumy,Ukraine

Speakers: Serhiy Mordyk (Institute of Applied Physics, National Academy of Sciences of the Ukraine)


Arc modeling at sumy ukraine

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


Arc modeling at sumy ukraine

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


Arc modeling at sumy ukraine

Setup for measurement of plasma parameters


Arc modeling at sumy ukraine

Time-resolved laser mass spectrometer


Arc modeling at sumy ukraine

Optical spectrometer


Arc modeling at sumy ukraine

Optical spectrum of nitrogen

Helicon discharge (IAP NASU)

Determination of vibrational and rotational

temperature is necessary for modeling of

kinetic of plasma processes


Arc modeling at sumy ukraine

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


Arc modeling at sumy ukraine

DC-spark (data from Jan Koverman)

Sample Cu 9(7)


Arc modeling at sumy ukraine

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


Arc modeling at sumy ukraine

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


Pic model

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


Arc modeling at sumy ukraine

Initial state of plasma

cathode

anode


Arc modeling at sumy ukraine

Electrons on the anode


Arc modeling at sumy ukraine

Ions CU on the cathode


Arc modeling at sumy ukraine

Ions CU on the cathode


Arc modeling at sumy ukraine

Fluid model

Equations system of the two fluids hydrodynamics

Poisson equations

A

Equation of motion

C

PLASMA


Integration model

Integration model

Vlasov–BoltzmannEquation:

Poisson’s equation

where na is the density:

Photoionization


Arc modeling at sumy ukraine

Thank you


Conclusion

Conclusion

It is necessary to know plasma parameters for arc modeling


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