Structure of stagnated plasma in aluminum wire array Z pinches

Hall, G. N.; Pikuz, S. A.; Shelkovenko, T. A.; Bland, S. N.; Lebedev, S. V.; Ampleford, D. J.; Palmer, J. B. A.; Bott, S. C.; Rapley, J.; Chittenden, J. P.; Apruzese, J. P.

doi:10.1063/1.2234284

Cited by 26 publications

(13 citation statements)

References 30 publications

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“…Formation of axial necks in the pinch due to the implosion inhomogeneity was observed in previous papers. 16,17,19,28,34,35 Figure 2 shows the dynamics of radiation from necks in an Al 4-ray 24-wire star array and a 10-wire planar load taken with the Au photocathode without filters, E > 50 eV, over a 50 ns range. The necks are seen as bright spots in the streak images.…”

Section: Resultsmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] In this introduction, we will use words bright spots, micro-pinches, hot spots, and plasma points, as they are mentioned in the original cited articles. Apparently, plasma instabilities generate areas in the pinch with a high plasma density and temperature.…”

Section: Introductionmentioning

confidence: 99%

“…4,[18][19][20] Continuum spectra of hot spots in the keV range may be a signature of a high plasma density. 16,17 Recently, axially resolved spectroscopy and K-shell power measurements were applied to stagnated Al, Cu, and Ti Z pinches on the Z machine. 22 Segments of the pinch containing bright spots were compared to segments without bright spots.…”

Section: Introductionmentioning

confidence: 99%

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Study of micro-pinches in wire-array Z pinches

et al. 2013

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Bright and hot areas with a high plasma density and temperature are observed in all kinds of Z pinches. We studied bright radiating spots produced by micro-pinches in cylindrical and planar wire-arrays at the 1 MA Zebra pulsed power generator using an x-ray streak camera synchronized with laser diagnostics, x-ray time-gated pinhole camera, and spectroscopy. Hot spots with extremely dense and relatively hot plasma arise during the collapse of the micro-pinches. These hot spots radiate a continuum spectrum with energy >2.5 keV. Typical micro-pinches in Al wire arrays generate x-ray bursts with durations of 0.4-1 ns in the soft x-ray range and 0.1-0.4 ns in the keV range. UV two-frame shadowgraphy shows spatial correlation of hot spots with the collapse and explosion of micro-pinches. Micro-pinches typically occur at the necks of the Z pinch, but can demonstrate a variety of parameters and different dynamics. An analysis of x-ray streak images shows that micro-pinches can generate >20% of the x-ray energy in some types of wire-array Z pinches. V C 2013 AIP Publishing LLC. [http://dx.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Study of micro-pinches in wire-array Z pinches

et al. 2013

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“…An estimate of the electron temperature of the plasma in the magnetic cavity was made using time-integrated X-ray spectroscopy (photon energy of hν>1 keV), which provided information about the hot, compressed part of the outflow. The spectrum was measured using a spherically bent mica crystal [33], which provided spatial resolution along the jet. An example of a spectrum obtained in these experiments is shown in Fig.…”

Section: E Temperature Of the Central Jetmentioning

confidence: 99%

Generation of episodic magnetically driven plasma jets in a radial foil Z-pinch

et al. 2010

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We present experimental results of the formation of magnetically driven plasma jets, showing for the first time a way of producing episodic jet/ouflows in the laboratory. The jets are produced using a 6.5 µm thick aluminum disc (a radial foil), which is subjected to the 1 MA, 250 ns current pulse from the MAGPIE generator [I. H. Mitchell et al., Rev. Sci. Instrum. 67, 1533(1996]. The early time motion of the foil is characterized by the bulk motion of the mass due to the magnetic pressure, together with the formation of a surface plasma following the direction of the J × B force. A low density plasma fills the region above the foil preceding the formation of subsequent magnetically driven jets on the axis of expanding magnetic bubbles. The outflows emerge in timescales of ∼30-40 ns and their episodic nature is the result of current reconnection in the foil, aided by the formation of current-driven instabilities in the jet and the distribution of mass available from the foil. The additional inductance due to the new current path inside the cavities was measured using an inductive probe, allowing to estimate the energy balance associated with the episodes. The measured temperature of the compressed jet resulted in Te∼300 eV and a magnetic Reynolds number of ReM ∼200-1000, allowing the experiments to be in the regime relevant for scaled representations of astrophysical outflows.

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“…The temperature of the plasma in the magnetic cavity was measured using time-integrated hard X-ray spectroscopy (photon energy of hν >1 keV), which provided information about the hot, compressed part of the outflow. The spectrum was measured using a spherically bent mica crystal (Hall et al 2006), which provided spatial resolution along the length of the jet. The electron temperature of the jet T e was estimated by considering the ratio of the combined intensity of Helium-like aluminum lines to Hydrogen-like aluminum.…”

Section: Temperature Of the Jetmentioning

confidence: 99%

Experimental Studies of Magnetically Driven Plasma Jets

Suzuki-Vidal

Lebedev

Bland

et al. 2010

Astrophys Space Sci

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We present experimental results on the formation of supersonic, radiatively cooled jets driven by pressure due to the toroidal magnetic field generated by the 1.5 MA, 250 ns current from the MAGPIE generator. The morphology of the jet produced in the experiments is relevant to astrophysical jet scenarios in which a jet on the axis of a magnetic cavity is collimated by a toroidal magnetic field as it expands into the ambient medium. The jets in the experiments have similar Mach number, plasma beta and cooling parameter to those in protostellar jets. Additionally the Reynolds, magnetic Reynolds and Peclet numbers are much larger than unity, allowing the experiments to be scaled to astrophysical flows. The experimental configuration allows for the generation of episodic magnetic cavities, suggesting that periodic fluctuations near the source may be responsible for some of the variability observed in astrophysical jets. Preliminary measurements of kinetic, magnetic and Poynting energy of the jets in our experiments are presented and F. Suzuki-Vidal ( ) · S.V. Lebedev · S.N. Bland · G.N. Hall ·

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Structure of stagnated plasma in aluminum wire array Z pinches

Cited by 26 publications

References 30 publications

Study of micro-pinches in wire-array Z pinches

Study of micro-pinches in wire-array Z pinches

Generation of episodic magnetically driven plasma jets in a radial foil Z-pinch

Experimental Studies of Magnetically Driven Plasma Jets

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