Jet Formation and Current Transfer in$X$-Pinches

Beg, F. N.; Ciardi, A.; Ross, I. N.; Zhu, Yanhe; Dangor, A. E.; Krushelnick, K.

doi:10.1109/tps.2006.878360

Cited by 26 publications

(22 citation statements)

References 14 publications

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“…More recently, Mitchell et al (2000) studied the behavior of the coronal plasma on a 450 kA x-pinch, and showed that the low-density coronal plasma contributes to jet formation through optical and XUV framing images. Beg et al (2006) made similar observations with a 160 kA generator, and additional investigations into the effects of wire coatings on the low density corona were reported by Haas et al (2007). These studies focused on the plasma evolution between the electrodes where the wire ablation contributed to the zippered formation of the plasma structure.…”

supporting

confidence: 62%

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Supersonic jet formation and propagation in x-pinches

Haas

Bott

Kim

et al. 2011

Astrophys Space Sci

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Observations of supersonic jet propagation in low-current x-pinches are reported. X-pinches comprising of four 7.5 µm diameter tungsten wires were driven by an 80 kA, 50 ns current pulse from a compact pulser. Coronal plasma surrounding the wire cores was accelerated perpendicular to their surface due to the global J × B force, and traveled toward the axis of the x-pinch to form an axially propagating jet. These jets moved towards the electrodes and, late in time (∼150 ns), were observed to propagate well above the anode with a velocity of 3.3 ± 0.6 × 10 4 m/s. Tungsten jets remained collimated at distances of up to 16 mm from the cross point, and an estimate of the local sound speed gives a Mach number of ∼6. This is the first demonstration that supersonic plasma jets can be produced using x-pinches with such a small, low current pulser. Experimental data compares well to three-dimensional simulations using the GORGON resistive MHD code, and possible scaling to astrophysical jets is discussed.

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supporting

confidence: 62%

“…A conventional Marx-driven generator (80 kA with a rise time of 40 ns [10%-90%]) was used to drive the x-pinch load with an approximately sin 2 current waveform, for a complete description see Beg et al (2006Beg et al ( , 2007. Four 7.5 µm tungsten wires were used to construct the x-pinches.…”

Section: Methodsmentioning

confidence: 99%

Supersonic jet formation and propagation in x-pinches

Haas

Bott

Kim

et al. 2011

Astrophys Space Sci

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“…Astrophysics-relevant bow shocks were produced in nested wire arrays [76], where radiatively cooled plasma streams ablated from the outer wires would flow around the wires of the inner array. It turned out that highly collimated, highMach-number jets can also be produced by a relatively lowcurrent X-pinch discharges [77], [78]. Sheared flows were produced and studied in [79].…”

Section: Similarity and Scaling Lawsmentioning

confidence: 99%

Characterizing the Plasmas of Dense $Z$ -Pinches

Ryutov

2015

IEEE Trans. Plasma Sci.

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This mini-tutorial summarizes the plasma characteristics important for the Z-pinch research, with an emphasis on high-density collisional plasmas. It begins with the discussion of the most basic plasma properties related to collisionality and magnetization and then proceeds to more complex phenomena associated with magnetic field evolution in a highly dynamical plasma. Plasma transport properties are discussed mostly in conjunction with the Magnetized Liner Inertial Fusion concept. Issues of interplay of the classical and anomalous transport in a plasma whose pressure is higher than the magnetic pressure are elucidated. Differences in magnetic reconnection in weakly versus highly collisional plasmas are discussed. Kinetic effects and the role of microturbulence are mentioned in conjunction with the formation of high-energy tails in the particle distribution functions and the generation of particle beams. The discussion is based on the order-of-magnitude estimates suitable for initial orientation in the problem. The two appendixes contain some auxiliary material.

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“…There is less emission from the "legs" of the four-wire X-pinch than from those of the twowire pinch-while there is significantly more emission from the cross point of the four-wire pinch. The jets propagating to the anode and cathode from the X-point are more prominent in the four-wire pinch, as evidenced by the plasma emission from the electrode material at both the cathode and the anode [5]. This indicates that the energy and/or electron density of the plasma jets has increased in the four-wire case.…”

mentioning

confidence: 93%

“…The random spatial and temporal behavior of these bright spots often makes the use of this source problematic [1]. X-pinches, however, which are formed by two or more wires placed between the electrodes, making the shape of the letter "X," are much more reproducible [2]- [5]. A well localized X-ray source can be produced at the cross point that can have an X-ray pulse duration less than 1 ns, a spot size less than 1 µm, and X-ray energies in the 1-10 keV range.…”

mentioning

confidence: 99%

Dynamics of Multiple-Wire X-Pinches

Green

Beg

Bland

et al. 2008

IEEE Trans. Plasma Sci.

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X-pinches are one of the most localized sources of X-rays and are potentially useful for a number of applications. An investigation was carried out into the plasma dynamics of a "tabletop" X-pinch plasma generated by passing a 40-ns 35-kA current pulse through two or four 5-µm-thick tungsten wires. It was found that the number of wires significantly changes the dynamics of the discharge, as evidenced by images of the emission in the visible spectral region. It was also found that increasing the number of wires enhanced the reproducibility of the discharge and the X-ray pulse. Index Terms-Plasma measurements, plasma pinch.A N IMPORTANT technological application of plasma physics is the use of discharges for the production of X-ray radiation. In Z-pinch discharges, in which a large current passes through a single wire, a series of bright X-ray emission regions located along the length of the wire are typically observed and are associated with the growth of magnetohydrodynamic (MHD) instabilities. The random spatial and temporal behavior of these bright spots often makes the use of this source problematic [1]. X-pinches, however, which are formed by two or more wires placed between the electrodes, making the shape of the letter "X," are much more reproducible [2]- [5]. A well localized X-ray source can be produced at the cross point that can have an X-ray pulse duration less than 1 ns, a spot size less than 1 µm, and X-ray energies in the 1-10 keV range. These parameters make X-pinches a particularly attractive source for many applications [2].Here, we report measurements of the effect of wire number on the detailed plasma structure and jet formation during the discharge-particularly on the radial emission of plasma from the X-point which has not been previously studied. Experiments were performed using X-pinches formed from two and four wires. In general, the use of four wires during these discharge resulted in more radiation emission, higher energy X-ray emission, and more consistent performance [4].In these experiments, a small four-capacitor Marx bank was used to pulse-charge a coaxial water dielectric line, which was switched by a self-breaking gas spark gap into an X-pinch load located in an evacuated chamber [3]. The total area of the generator and X-pinch chamber was about 0.5 m 2 . The

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Jet Formation and Current Transfer in$X$-Pinches

Cited by 26 publications

References 14 publications

Supersonic jet formation and propagation in x-pinches

Supersonic jet formation and propagation in x-pinches

Characterizing the Plasmas of Dense $Z$ -Pinches

Dynamics of Multiple-Wire X-Pinches

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