PulsedPower Plasma and its Applications

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Pulsed-Power Plasma and its Applications

• Pulsed Power What is this?
• Z-pinch
• Plasma Opening Switch
• Plasma as a source for intense electron/ion
  emission
• High-current electron and ion beams

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What is Pulsed Power ?Power 109-1014W,
Energy 105-107eV, Current
104-107A, Pulse duration 10-9-10-5 s

• slow storage compression stages forming
  elements load
• 
  
  switches
• Slow storage of energy (100-2 s)
• Compression stages (10-6 - 10-7 s)
• Forming and Transmission Elements (10-8 s)
• Load electron and ion diodes, z-pinches,
  antenna.
• Product pulsed power discharges, beams of
  charged particles, X-rays, neutron bursts, plasma
  heating, microwaves, laser beams, magnetic field
  compression.

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Pulsed Power Applications

• Inertial Confinement Fusion
• 2H1 3H1 4He2 (3.6 MeV)1n0 (14 MeV)
• Nit gt 1014s/cm3 (Ti ? 10 keV)
• Target compression of 104-105 is required (r0 ?
  1025 - 1026cm-3)
• Pressure ? 1015 Pa, Energy ? 106 J, Power ? 1014
  W/cm2
• Laser Beams
• Electron/Ion Beams
• Soft X-rays (Z-pinch)

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Pulsed Power Applications

• High-Power Bremsstrahlung Sources (electron
  beams)
• Dose Ee2.8Ie (HERMES III 20MeV, 700kA,
  30ns 100 kRad at 500 cm2)
• High-Power Soft X-ray Sources (Z-pinch
  efficiency 30)
• Eg 0.1 - 20keV (K, L shells), Energy
  0.5 - 2 MJ, Power ? 1012-1014 W
• High Intensity Neutron Fluxes
• Ion beam 1013 1n0/pulse (106 - 107
  1n0/J)
• Yield (Ei 105-107eV) 10-6-10-2 1n0/d
• Z-pinch 1012 1n0/pulse (105 - 106
  1n0/J)
• Strong Shock Wave Generation (electron and ion
  beams)
• Pressure Pb ??/(S?)
• Pb 1013 W/cm3 Pressure 10Mbar

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Pulsed Power Applications

• Ultra-High Intensity Pulsed Magnetic Field
• High-Power Pulsed Gaseous Lasers
• High-Power Microwaves
• Strengthening and Modification of Materials
• Thin Film Preparation

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Z-pinch

• Electric energy Magnetic field energy Kinetic
  energy Thermal energy Radiation

Soft X-ray
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X-Accelerator (Sandia National Laboratories)Achie
ved X-ray output 1.9 MJ, 280 TW, 200 eV
Required X-ray output 10 MJ, 1000 TW, 230 eV
Expected target energy 1000 MJ
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Z-pinch phenomena

• Rapid breakdown, ionization, and heating of
  initially cold gas or wire material that is
  turned into plasma
• Interaction of conducting plasma with the
  magnetic field
• Radiation and plasma instabilities
• The Bennett equilibrium (1934), balance between
  kinetic and magnetic pressures
• The Pease-Braginskii equilibrium (1957),
  balance between Ohmic (Spitzer) heating and
  radiative (bremsstrahlung) cooling
• Radiative collapse
• Bulk of the radiation is emitted in the
  soft x-ray region of the spectrum (10-5000 eV)
  due to bremsstrahlung (free-free), recombination
  (free-bound) and line emission (bound-bound)
  radiation.
• Plasma instabilities MHD instabilities,
  current driven kinetic instabilities.
  Micro-pinches (ne 1023cm-3, T 1 keV),
  non-thermal electron and ion beams, leakage
  current outside the Z pinch, transition from
  optically thin to optically thick plasma state,
  etc.

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Plasma Opening Switch
V.M.Bystritskii, A.A.Kim, Ya.E.Krasik,
B.M.Koval'chuk, and G.A.Mesyats, Microsecond
plasma opening switches, Physics of Elementary
Particles and Atomic Nuclei, 23, 19 (1992).
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Plasma Opening Switch

• Main Physical Phenomena
• Anomalous fast magnetic field penetration
• Classical diffusion time
• Experiment 10-8 - 10-6 s
• Fast increase of the plasma resistivity 107-109
  W/s
• Mechanism of generation of high-current electron
  and ion beams during the POS opening

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Anomalous fast magnetic field penetration

• Electron Magnetohydrodynamics (Hall effect )
• ? ? 10-8 - 10-6 s
• Current channel d gtgt (c/wpe) ???
• Energy dissipation mechanism ???
• Competition with snowplow model at nigt1015 cm-3
  ???

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Axial current distribution during conduction
phase
V. M. Bystritskii, Ya.E.Krasik, I.V.Lisitsin, and
A. S. Sinebrukhov, Sov. J. Plasma Phys. 217, 34
(1991)
M.Sarfaty, Y.Maron, Ya. E.Krasik, A.Weingarten,
R.Arad, R.Shpitalnik, A.Fruchtman, and S.Alexiou,
Phys. of Plasmas, 2, 2122 (1995).
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Fast increase of the plasma resistivity

• Double layer formation with plasma
  quasi-neutrality violation
• Hall resistivity with keeping plasma
  quasi-neutrality

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Fast increase of the plasma resistivity
Fast propagating ion flow
Fast oscillating electric field
E 10 kV/cm
S.Alexiou, A.Weingarten, Y.Maron, M.Sarfaty and
Ya.E.Krasik, Phys. Rev. Lett. 75, 3126 (1995).
Ya. E. Krasik, A. Weingarten, IEEE Trans. Plasma
Science 26, 208, 1998.
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Generation of energetic charged particles
Bremsstrahlung radiation along the anode (?c1.1
?s, Iu 250 kA). G.A.Mesyats, A.N. Didenko,
Ya.E. Krasik, et al., Sov. Phys. Dokl., 31, 557
(1986)
Axial distribution of proton current density
along the cathode (tc0.9 ms, Iu 240 kA). 1.
Short-circuit. 2. Electron diode. E.N.Abdullin,
B.M.Koval'chuk, Ya.E.Krasik, et al., Sov. J.
Plasma Phys., 13, 589 (1987)
Ion beam current density measured at different
distances from the load side edge of the plasma.
Ya. E. Krasik, A. Weingarten, IEEE Trans. on
Plasma Science 26, 208, 1998
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Generation of energetic charged particles
POS opening phase is accompanied by the
generation of high-current energetic
electron and ion beams and microwave radiation
Ya.E.Krasik, R.Arad, A.Weingarten, and Y.Maron,
Proc.10th Intern. Conf. on High Power Particle
Beams, Prague,pp. 1039-1045, 1996.
Ya. E. Krasik, A. Dunaevsky, J. Felsteiner, and
J. Goyer, J. Appl. Phys. 85, 686 (1999).
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Explosive Emission Plasma
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Flashover Plasma (passive cathodes)
Formation of emission centers depends strongly on
the growth rate of the electric field
Carbon fiber cathode
Ya. E. Krasik, A. Dunaevsky, J. Felsteiner, et
al., J. Appl. Phys. 89, 2379 (2001)
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Flashover Plasma (ferroelectric active cathodes)
Plasma model
Polarization Reversal model
Light Emission (large area BaTiO3 cathode)
PCB (e3) Frame 10 ns
G. Rosenman, D. Shur, Ya. E. Krasik, A.
Dunaevsky, Review Ferroelectric cathodes. J.
Appl. Physics, 88, 6109 (2001) Ya. E. Krasik,
A. Dunaevsky, and J. Felsteiner, Appl. Phys.
Lett. 73, 453 (1998) Ya. E. Krasik, A.
Dunaevsky, J. Felsteiner, J. Appl. Phys. 85, 7946
(1999)
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High-current electron beams

• Alfven (1939) current IA 17bg kA
• Lawson (1957) current IL IAb2(b2 f - 1)-1, f
  (ni/ne)
• Space-charge-limiting current Is-ch (mec3/2e)(g
  2/3 - 1)3/2/12ln(R/rb)

Beam instabilities
Electron Ring
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High -current electron beams

• 
  

Planar diode
EA EC QiQe Iete Iiti
Ie Ii(mi/me)1/2
Magnetically insulated foilless diode
Pinch-diode
Self-magnetic field of the electron current leads
to pinch effect
Space-charge limiting current
Parapotential current
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High-current electron diode
Ferroelectric plasma cathode
Example of closure of Anode-Cathode gap by
plasma dac 20mm, Ua 180 kV, I 2.5 kA. Frame
10 ns
Front view
Side view
X-ray image
Potential distribution in the plasma prefilled
diode
dac 40mm, Ua 180 kV, I 2.5
kA Frame 10
ns 0 200 ns
400ns
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High current ion beams

• Planar bipolar diode Ii Ie(me/mi)1/2
• It is necessary to increase life-time of
  electrons in the anode-cathode gap

Pinch diode
Reflex systems
V. M. Bystritskii, Ya.E.Krasik, and G.A.Mesyats,
Phys. of Elementary Particles and Atomic Nuclei
22, 1171 (1991)
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High current ion beams

• Magnetically self or externally insulated ion
  diodes

PFBA II Li-ion beam Ei 6 MeV, t 25 ns Ii
1 MA, 1.4 TW/cm2 Li-Target - 100 eV (necessary
for ignition 5 TW/cm2)
V. M. Bystritskii, S. N. Volkov, Ya. E. Krasik,
et al., Sov. J. Plasma Phys., 14, 262 (1988)