New model of calculating the energy transfer efficiency for the spherical theta-pinch device

Xu, Genhui; Hock, Christian; Loisch, Gregor; Xiao, Guoqing; Jacoby, J.; Weyrich, K.; Lü, Ying; Zhao, Yongtao

doi:10.1063/1.4919938

Cited by 5 publications

(4 citation statements)

References 15 publications

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“…This 80 MHz carrier is eliminated by 30 MHz low pass filters at the outputs of the I/Q-demodulator. Before using equation (8), deviations from the ideal equations ( 6) and ( 7) resulting from imperfect electrical components in the I/Q-demodulator are corrected by calibration procedures [25,26,38]. Additionally, all electrical components used in this set-up are contained inside a Faraday cage to shield them from the electromagnetic noise produced during the discharge.…”

Section: Single Wavelength Interferometermentioning

confidence: 99%

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Measurement of the free electron line density in a spherical theta-pinch plasma target by single wavelength interferometry

Christ

Cistakov

Iberler

et al. 2021

J. Phys. D: Appl. Phys.

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A single wavelength heterodyne interferometer has been set up to investigate the free electron density integrated axially along the line of sight (line density) in a theta-pinch plasma to determine its applicability as a plasma target for ion beam stripping. The maximal line density reached in this experiment was 3 . 57 ± 0 . 28 × 10 18 cm−2 at 80 Pa and 20 kV. The findings demonstrate the pulsed character of the line density and its increase by raising the load voltage and the working gas pressure. Additionally, the results were compared with spectroscopic free electron density estimations, which were carried out by H β -line broadening and peak separation. The time behavior of the line density indicates that its peak value is delayed by about 10 µs compared to the spectroscopic results. This effect is due to the formation of an extended, magnetically compressed plasma column in the vicinity of the current maximum, although the highest volumetric free electron density is reached near the current zero crossing. Since the line density is an essential parameter in describing the stripping capabilities of the plasma target, the interferometric diagnostic is superior to a spectroscopic diagnostic, because it directly provides integrated values along the line of sight. Furthermore, the measurements of the line density in this experiment partially show nonphysical negative values, which is due to gaseous effects and residual shot vibrations.

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Section: Single Wavelength Interferometermentioning

confidence: 99%

“…Our theta-pinch devices, however, were developed to study ion beam plasma interaction for ion beam stripping [5][6][7][8]. When an ion beam interacts with a fully ionized plasma target, collisions of the projectile with free plasma particles (electrons and ions) lead to a stripping of the projectile electrons [9,10].…”

Section: Introductionmentioning

confidence: 99%

Measurement of the free electron line density in a spherical theta-pinch plasma target by single wavelength interferometry

Christ

Cistakov

Iberler

et al. 2021

J. Phys. D: Appl. Phys.

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“…Moreover, electrode sputtering contaminating the plasma and limiting the target durability is a general problem in linear discharges. Consequently, an electrode-less inductively coupled plasma target was created by a theta-pinch set-up [9][10][11][12]. In these experiments, mostly spectroscopic diagnostics have been carried out to determine the free electron density and temperature.…”

Section: Introductionmentioning

confidence: 99%

Time-resolved measurement of the free electron and neutral gas line density in a hydrogen theta-pinch plasma target by two-color interferometry

Christ

Guzmán

Cistakov

et al. 2022

J. Phys. D: Appl. Phys.

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A hydrogen theta-pinch plasma is diagnosed by two-color interferometry to determine the line density of the free electrons and the hydrogen gas. From the ratio of these line densities, the effective ionization can be calculated. The free electron line density and the effective ionization degree are the most essential quantities for the evaluation of the plasma regarding its applicability as a target in context of plasma ion beam interaction to increase the charge state of the ion beam (plasma stripper). The two-color interferometric diagnostic shows that both line densities exhibit a periodic behavior predefined by the periodic current and at the time the free electron line density reaches a local maximum, the hydrogen line density falls to a local minimum. This occurs, because the plasma is axially ejected from the coil center by evading the radial compression force of the magnetic field, creating an ionizing wave in the residual gas. The theta-pinch was set up in two versions, with one of them using a cylindrical coil and the other using a spherical coil. For the cylindrical version, the best working point regarding the free electron line density and the effective ionization degree is (1.45±0.04)·1018 cm-2 and (0.826±0.022) at 20 Pa and 16 kV. In contrast, for the spherical version, lower values of (1.23±0.03)·1018cm-2 and (0.699±0.019) at 20 Pa and 18 kV were found. Additionally, a new set-up is proposed for optimizing the plasma target regarding the free electron line density and the effective ionization degree, as well as how to maintain them on a sufficient level for several 10 µs.

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“…In the experiments described here, a spherical theta pinch has been used as a plasma device, as described in Refs. [16][17][18][19][20][21][22][23][24]. The energy stored in a capacitor bank is transferred to the target by a coil surrounding a 4 l glass vessel filled with the working gas.…”

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confidence: 99%

Determination of Hydrogen Density by Swift Heavy Ions

Barriga-Carrasco

Blažević

et al. 2017

Phys. Rev. Lett.

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A novel method to determine the total hydrogen density and, accordingly, a precise plasma temperature in a lowly ionized hydrogen plasma is described. The key to the method is to analyze the energy loss of swift heavy ions interacting with the respective bound and free electrons of the plasma. A slowly developing and lowly ionized hydrogen theta-pinch plasma is prepared. A Boltzmann plot of the hydrogen Balmer series and the Stark broadening of the H_{β} line preliminarily defines the plasma with a free electron density of (1.9±0.1)×10^{16} cm^{-3} and a free electron temperature of 0.8-1.3 eV. The temperature uncertainty results in a wide hydrogen density, ranging from 2.3×10^{16} to 7.8×10^{18} cm^{-3}. A 108 MHz pulsed beam of ^{48}Ca^{10+} with a velocity of 3.652 MeV/u is used as a probe to measure the total energy loss of the beam ions. Subtracting the calculated energy loss due to free electrons, the energy loss due to bound electrons is obtained, which linearly depends on the bound electron density. The total hydrogen density is thus determined as (1.9±0.7)×10^{17} cm^{-3}, and the free electron temperature can be precisely derived as 1.01±0.04 eV. This method should prove useful in many studies, e.g., inertial confinement fusion or warm dense matter.

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New model of calculating the energy transfer efficiency for the spherical theta-pinch device

Cited by 5 publications

References 15 publications

Measurement of the free electron line density in a spherical theta-pinch plasma target by single wavelength interferometry

Measurement of the free electron line density in a spherical theta-pinch plasma target by single wavelength interferometry

Time-resolved measurement of the free electron and neutral gas line density in a hydrogen theta-pinch plasma target by two-color interferometry

Determination of Hydrogen Density by Swift Heavy Ions

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