Measuring the plasma density of a ferroelectric plasma source in an expanding plasma

Dunaevsky, A.; Fisch, Nathaniel J.

doi:10.1063/1.1690860

Cited by 13 publications

(6 citation statements)

References 20 publications

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“…Another large-volume plasma source involves a design based upon the use of ferroelectric materials [30], which can be used as large-surface-area electron emitters capable of producing high current densities [31,32]. The principle of operation for a plasma source made of ferroelectric ceramic relies on large dielectric constants to amplify local surface electric fields.…”

Section: Ferroelectric Plasma Sourcementioning

confidence: 99%

Advanced plasma flow simulations of cathodic-arc and ferroelectric plasma sources for neutralized drift compression experiments

Sefkow

Davidson

Gilson

2008

Phys. Rev. ST Accel. Beams

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Large-space-scale and long-timescale plasma flow simulations are executed in order to study the spatial and temporal evolution of plasma parameters for two types of plasma sources used in the neutralized drift compression experiment (NDCX). The results help assess the charge neutralization conditions for ion beam compression experiments and can be employed in more sophisticated simulations, which previously neglected the dynamical evolution of the plasma. Three-dimensional simulations of a filtered cathodic-arc plasma source show the coupling efficiency of the plasma flow from the source to the drift region depends on geometrical factors. The nonuniform magnetic topology complicates the wellknown general analytical considerations for evaluating guiding-center drifts, and particle-in-cell simulations provide a self-consistent evaluation of the physics in an otherwise challenging scenario. Plasma flow profiles of a ferroelectric plasma source demonstrate that the densities required for longitudinal compression experiments involving ion beams are provided over the drift length, and are in good agreement with measurements. Simulations involving azimuthally asymmetric plasma creation conditions show that symmetric profiles are nevertheless achieved at the time of peak on-axis plasma density. Also, the ferroelectric plasma expands upstream on the thermal expansion time scale, and therefore avoids the possibility of penetration into the acceleration gap and transport sections, where partial neutralization would increase the beam emittance. Future experiments on NDCX will investigate the transverse focusing of an axially compressing intense charge bunch to a sub-mm spot size with coincident focal planes using a strong final-focus solenoid. In order to fill a multi-tesla solenoid with the necessary high-density plasma for beam charge neutralization, the simulations predict that supersonically injected plasma from the lowfield region will penetrate and partially fill the high-field region of the solenoid. Because of the magnetic mirroring effect, the on-axis plasma density in the solenoid depends on the injection velocity and magnetic field strength.

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Section: Ferroelectric Plasma Sourcementioning

confidence: 99%

Advanced plasma flow simulations of cathodic-arc and ferroelectric plasma sources for neutralized drift compression experiments

Sefkow

Davidson

Gilson

2008

Phys. Rev. ST Accel. Beams

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“…The plasma density and temperature averaged over space ( 1 mm) and time ( 100 ns) were found to be in the range 10 11 -10 13 cm −3 and 2-8 eV, depending on the ferroelectric sample composition and polarity, amplitude and form of the driving pulse [8]. The plasma density at the triple points was estimated to be up to 10 17 cm −3 [9]. Here let us note that numerous experimental and theoretical research works on dielectric surface flashover in gas and vacuum have been carried out in the last 50 years and many scientific papers have been published on this subject [10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 96%

Energetic particle and photon emission during dense plasma formation at the ferroelectric surface

Yarmolich¹,

Vekselman²,

Gurovich³

et al. 2008

Plasma Sources Sci. Technol.

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The operation of ferroelectric plasma sources (FPSs) under the application of driving pulses with different amplitudes (4-40 kV) was studied. It was found that the dense plasma formation during the fast fall (a few tens of nanoseconds) in the driving pulse is accompanied by the generation of a highly diverging (∼180 • ) neutral flow with a velocity of ∼7 × 10 7 cm s −1 in addition to the electron/ion and charged micro-particle flows which were studied in earlier research. It was shown that the velocity and intensity of the generated neutral flow remained the same for different parameters of the driving pulse. In addition a flux of x-rays with an energy of ∼20 keV was observed for ∼2 µs after the ending of the 40 kV driving pulse. A model of neutral emission based on micro-explosions of ferroelectric ceramics is suggested.

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“…Ferroelectric materials have been intensively examined as high-current density electron emitters [5][6][7]. They have been projected to serve as large-surface area, high-current density cathodes.…”

Section: Ferroelectric Plasma Sourcementioning

confidence: 99%

Ferroelectric plasma source for heavy ion beam space charge neutralization

Efthimion

Gilson

Davidson

et al. 2007

Nuclear Instruments and Methods in Physics Research Section A:

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Plasmas are a source of unbound electrons for charge neutralizing intense heavy ion beams to allow them to focus to a small spot size and compress their axial pulse length. The plasma source should be able to operate at low neutral pressures and without strong externally applied electric or magnetic fields. To produce 1 m-long plasma columns, sources based upon ferroelectric ceramics with large dielectric coefficients are being developed. The sources utilize the ferroelectric ceramic BaTiO 3 to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) will be covered with ceramic material, and high voltage ($7 kV) will be applied between the drift tube and the front surface of the ceramics. A prototype ferroelectric source, 20 cm in length, has produced plasma densities of 5 Â 10 11 cm À3. It was integrated into the Neutralized Transport Experiment (NTX), and successfully charge neutralized the K + ion beam. A 1 m-long source comprised of five 20-cm-long sources has been tested. Simply connecting the five sources in parallel to a single pulse forming network power supply yielded non-uniform performance due to the time-dependent nature of the load that each of the five plasma sources experiences. Other circuit combinations have been considered, including powering each source by its own supply. The 1-m-long source has now been successfully characterized, producing relatively uniform plasma over the 1 m length of the source in the mid-10 10 cm À3 density range. This source will be integrated into the NDCX device for charge neutralization and beam compression experiments. r

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Measuring the plasma density of a ferroelectric plasma source in an expanding plasma

Cited by 13 publications

References 20 publications

Advanced plasma flow simulations of cathodic-arc and ferroelectric plasma sources for neutralized drift compression experiments

Advanced plasma flow simulations of cathodic-arc and ferroelectric plasma sources for neutralized drift compression experiments

Energetic particle and photon emission during dense plasma formation at the ferroelectric surface

Ferroelectric plasma source for heavy ion beam space charge neutralization

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