Fiber Ablation in the Solid-Deuterium<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Z</mml:mi></mml:math>Pinch

Lindemuth, I.R.; McCall, Gene H.; Nebel, Richard

doi:10.1103/physrevlett.62.264

Cited by 29 publications

(19 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[5][6][7][8] The results are also consistent with observation of Aivozov et al, 14 who reported a precursor plasma on axis before the wire array arrives; and the calculation Bobrova et al, 5 who predicted that the magnetic force on these inhomogeneous currents will pull them apart. The results are at odds with the conclusions drawn by Bloomberg et al 4 that the vaporization and ionization phase of the wires in an array is so short as to be of no consequence, and that the self-magnetic field of each wire will maintain their spatial integrity.…”

Section: Mg Coated Al Loadssupporting

confidence: 84%

“…These processes have been considered theoretically by numerous researchers. [5][6][7][8] HY-Tech's results also reveal parasitic current channel formation that has not been addressed in previous studies. These parasitic currents are formed by prepulse currents, flowing in the load, which outgas the wire at current levels below that required to vaporize the surface.…”

Section: B Current Channel Formationmentioning

confidence: 95%

“…4 Numerous theoretical studies have predicted current carrying fibers or wires to be heterogeneous with a tenuous corona plasma, which carries most of the current, surrounding a core in various degrees of vaporization and ionization. [5][6][7][8] The inhomogeneous nature of the current channel has significant impact on the dynamics of the pinch. Lindenmuth et al 6 have attributed the MHD stability of frozen D 2 fiber loads to a solid core that persists throughout a significant fraction of the current pulse.…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7][8] The inhomogeneous nature of the current channel has significant impact on the dynamics of the pinch. Lindenmuth et al 6 have attributed the MHD stability of frozen D 2 fiber loads to a solid core that persists throughout a significant fraction of the current pulse. Bobrova et al 5 have concluded that the collective magnetic force on an array element is spatially inhomogeneous over its cross section if the current distribution is inhomogeneous.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Evidence for precursor plasma formation resulting from heterogeneous current channels in wire array loads

Yadlowsky¹,

Moschella²,

Hazelton³

et al. 1996

Physics of Plasmas

View full text Add to dashboard Cite

The initial current flow in single and double wire loads exploded by current generators with dI/dt in the range of 10 10 -10 12 A/s has been investigated using laser absorption and interferometric techniques. The results clearly show heterogeneous current channel formation with a plasma corona surrounding a predominantly neutral core. In the two wire load case, the corona is observed to separate from the core and prematurely implode on axis. Parasitic current channels were observed when material, outgassed by a low level prepulse current, is ionized to form a current carrying plasma channel that temporarily shields the wire from the main current pulse. In a complementary study on a terawatt generator, the radiation spectra from Mg coated Al wire array loads contained Mg K-shell lines 10 ns before similar Al lines were observed, confirming the load straggling effects implied by the laser imaging measurements. The results are consistent with theoretical predictions of heterogeneous current channels and precursor plasma formation that lead to a softer implosion, reduced ion density, and reduced x-ray yield.

show abstract

Section: Mg Coated Al Loadssupporting

confidence: 84%

Section: B Current Channel Formationmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evidence for precursor plasma formation resulting from heterogeneous current channels in wire array loads

Yadlowsky¹,

Moschella²,

Hazelton³

et al. 1996

Physics of Plasmas

View full text Add to dashboard Cite

show abstract

“…Nevertheless, none of these improvements could explain the experimentally observed stability. With the use of a "cold-start" MHD simulation, Lindemuth et al calculated that the enhanced stability was due to the presence of the solid core of a fiber which lasted for a very long time [4]. The subsequent calculation showed that rather than enhancing the stability the core partially masked the evidence of instabilities [5].…”

Section: Introductionmentioning

confidence: 99%

Carbon fiber Z-pinch driven by microsecond-long capacitive discharge

2004

View full text Add to dashboard Cite

Fiber Z-pinch experiments were carried out at the Czech Technical University in Prague using a single capacitor of 3 μF charged to 20 kV. The current was peaking at ≈ 70 kA with a quarter period of ≈ 850 ns. Carbon fibers of 15 μm diameters and 7 ÷ 10 mm lengths were used as a load. For observing plasma dynamics, different diagnostic tools were used simultaneously: filtered PIN diodes, a gated XUV spectrometer, time-integrated and gated pinhole cameras, and schlieren photography.XUV pulses with a FWHM of 10 ÷ 30 ns were observed 200 ÷ 400 ns after the current breakdown. Right before XUV pulses, there were often noticeable drops in the circuit dI/dt. These dI/dt drops occurred at the same time as the implosion of a coronal plasma onto a fiber. XUV radiation was emitted from that part of a fiber where an m = 0 instability was developed. After the peak of XUV radiation, the m = 0 unstable plasma column rapidly expanded.The significant influence of evaporated material from electrodes was observed later than 500 ns after the breakdown. At that time, schlieren images showed that several parts of a fiber had already been totally ablated. The observed plasma column seemed to be MHD unstable and when m = 0 instabilities developed, X-ray pulses were detected. The energy of >1 keV photons exceeded 10 mJ.PACS: 52.58.Lq

show abstract

The high-density Z-pinch as a pulsed fusion neutron source for fusion nuclear technology and materials testing

1989

View full text Add to dashboard Cite

The dense Z-pinch (DZPl is one of the earliest and simplest plasma heating and confinement schemes, Recent experiment al advances based on plasma initiation from hair-like (10s pm in radius) solid hydrogen fiiaments have so far not encountered tlie usually devastating MHD instabilities that plagued early DZP experimenters. These encouraging results alorg with debut of a number of proof-of principle, high-current (1-2 MA in 10-100 ns) experiments have prompted consideration of the DZP as a pulsed source of DT fusion neutrons of sufficient strength (SN~1019 n/s) to provide uncollided neutron fluxes in excess of lW = 5-10 MW'/7n2 over test volumes of 10-30 !it re or greater. W1.ile this neutron source would be pulsed (100s 12s pulse widths, 10-100 Hz pulse rate), giving flux time compressions in the range 105-106, its simphcit.y, near-term feasibility, low cost, high-Q operation, and relevance to fusion systems that may provide a ptdsed commercial end-product (e.g., inertial confinement or the DZP itself) together create the impetus for preliminary consideration as a Iieut.ron source for fusion nuclear technology and materials testings, The results of a preliminary parametric systems study (focusing primarily on physics issues), conceptual design, and cost versus performance analyses are presented. The DZP promises an inexpensive and efficient, means to provide pulsed DT neutrons at an average rate in excess of 1019 n/s, with neutron currents Iu, X: 10 M W/m2 over volumes v esp 2 30 lit.re using single-pulse teclmologim that differ little from those being Ilsed in present-day experilllelltf. 1. INTRODUCTION [rapwtl-zpinch-6 /7/09-1 magnetohydrodynamic (MHD) deformations. Linear, ideal (zero resistivit.y) MHD theory predicts3-s reduced growth rates, or even stability for the m = O mode, if the current profiles are sufficiently diffuse. Minimum pressure profiles for which the m = O nlode is 4'5 The stabilizing effects of external gss ideally and linearly stable have been reported, pressure4 or finite ion Larmor radiuse have also been suggested, The development of improved high-voltage, pulsed-diagnostic, and pi:lcll-forlllatioll techniques together have led to improved results for the DZP7 and an emanced appreciation for the impact of formation conditions and plasma profiles on the pinch behavior. Recent DZP experiments at Los Alan~os8~g and at the Naval Research Laboratory 10 have initiated high-voltage discharges through small-radius (10-40 pm), solid-deuterium fibers. These I = 0.3-0.6 MA experiments do not observe the m = 1 kink instability, and the m = O sausage instability y is suppressed for 100s of Alfv6n transit times across the pinch radius as long as the plasma current is increasing (~> O). While transport and stability analysesl 1'12 are being conducted using three-dimensional resistive models in both linear aud non-linear regimes, the stability of these fiber initiated DZPS remains enigmatic, indicating the in~portance of formation method, pinch profiles, local (edge-plasma) dissipation, and dynamic stabi...

show abstract

Fiber Ablation in the Solid-DeuteriumZPinch

Cited by 29 publications

References 5 publications

Evidence for precursor plasma formation resulting from heterogeneous current channels in wire array loads

Evidence for precursor plasma formation resulting from heterogeneous current channels in wire array loads

Carbon fiber Z-pinch driven by microsecond-long capacitive discharge

The high-density Z-pinch as a pulsed fusion neutron source for fusion nuclear technology and materials testing

Contact Info

Product

Resources

About