Prolonged plasma production at current-driven implosion of wire arrays on Angara-5-1 facility

Alexandrov, V. V.; Frolov, I. N.; Fedulov, M. V.; Grabovsky, E. V.; Mitrofanov, K. N.; Nedoseev, S. L.; Oleĭnik, G. M.; Porofeev, I. Yu.; Samokhin, A. A.; Sasorov, P. V.; Smirnov, V. P.; Volkov, G. S.; Zurin, M.M.; Zukakischvili, G. G.

doi:10.1109/tps.2002.1024290

Cited by 88 publications

(25 citation statements)

References 7 publications

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“…(8) suggests the wire ablation rate to be proportional to the power deposition due to the Ohmic heating R Ω [I n0 ] 2 , where R Ω is the electric resistance of the wire. In the meantime, for the cylindrical arrays with higher wire number the lower values of the parameter α have been suggested: α = 1.8 for the intermediate wire number N = 60 − 80 cylindrical array loads at 3 MA current level [27,28], and α = 1.4 − 1.55 for the high wire number N = 200 − 300 cylindrical wire array loads at 20 MA current level [20,21].…”

Section: B Mass and Momentum Redistributionmentioning

confidence: 99%

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Wire ablation dynamics model and its application to imploding wire arrays of different geometries

et al. 2012

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The paper presents an extended description of the amplified Wire Ablation Dynamics Model (WADM) that accounts in a single simulation for the processes of the wire ablation and implosion of a wire array load of arbitrary geometry and wire material composition. To investigate the role of the wire ablation effects, the implosions of cylindrical and planar wire array loads at the university based generators Cobra (Cornell University) and Zebra (University of Nevada, Reno) have been analyzed. The analysis of the experimental data shows that the wire mass ablation rate can be described as a function of the current through the wire and some coefficient defined by the wire material properties. The aluminum wires were found to ablate with the highest rate, while the copper ablation is the slowest one. The lower wire ablation rate results in higher inward velocity of the ablated plasma, higher rate of the energy coupling with the ablated plasma, and more significant delay of implosion for a heavy load due to the ablation effects, which manifest the most in a cylindrical array configuration and almost vanish in a single planar array configuration. The WADM is an efficient tool suited for wire array load design and optimization in wide parameter ranges, including the loads with specific properties needed for the Inertial Confinement Fusion research and laboratory astrophysics experiments. The data output from the WADM simulation can be used to simplify the radiation MHD modeling of the wire array plasma.

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Section: B Mass and Momentum Redistributionmentioning

confidence: 99%

“…The smoothed shape of the thermalization rate P * (t), which is calculated according to Eq. (27), is compared with the experimental x-ray pulse in Fig. 9.…”

Section: B Double Planar Wire Arraymentioning

confidence: 99%

Wire ablation dynamics model and its application to imploding wire arrays of different geometries

et al. 2012

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“…Another important aspect of wire array operation is the existence of an extended ablation phase [16][17][18][19][20][21] before the main implosion. During this phase, which may last 50%-80% of the total implosion time, plasma is continuously generated at the surface of the dense, stationary wire cores and accelerated towards the axis by the J Â B force.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of the current switch mechanism in two-stage wire array Z-pinches

et al. 2015

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In this paper, we describe the operation of a two-stage wire array z-pinch driven by the 1.4 MA, 240 ns rise-time Magpie pulsed-power device at Imperial College London. In this setup, an inverse wire array acts as a fast current switch, delivering a current pre-pulse into a cylindrical load wire array, before rapidly switching the majority of the generator current into the load after a 100–150 ns dwell time. A detailed analysis of the evolution of the load array during the pre-pulse is presented. Measurements of the load resistivity and energy deposition suggest significant bulk heating of the array mass occurs. The ∼5 kA pre-pulse delivers ∼0.8 J of energy to the load, leaving it in a mixed, predominantly liquid-vapour state. The main current switch occurs as the inverse array begins to explode and plasma expands into the load region. Electrical and imaging diagnostics indicate that the main current switch may evolve in part as a plasma flow switch, driven by the expansion of a magnetic cavity and plasma bubble along the length of the load array. Analysis of implosion trajectories suggests that approximately 1 MA switches into the load in 100 ns, corresponding to a doubling of the generator dI/dt. Potential scaling of the device to higher current machines is discussed.

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“…From the comparison of the data in [19 and 20] (in the logarithmic scale), it follows that, for operation conditions of [21], the expansion velocity should increase two times and achieve ∼1.2 µm/ns. A verification of this estimate of the core expansion velocity seems to be especially urgent due to the presence of a strong collective magnetic field, which disturbs a cylindrical symmetry of a single wire.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Plasma‐Producing Structures at Current Implosion of a Wire Array

Grabovsky

Mitrofanov

Nedoseev

et al. 2005

Contrib. Plasma Phys.

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Characteristic properties of the plasma production process have been considered for the case of megampere currents flowing through hollow cylindrical wire arrays of the Angara-5-1 facility. In 3-4 nanoseconds after voltage applying to the wire surfaces there appear a plasma layer. The system becomes heterogeneous, i.e. consisting of a kernel of metal wires and a plasma layer. In several nanoseconds the current flow goes from metal to plasma, which results in reducing the electric field strength along the wire.The Joule heat energy delivered to the metal before the moment of complete current trapping by plasma is insufficient for the whole mass transition to a hot plasma state. The X-ray radiography techniques made it possible to detect and study dense clusters of substance of ∼1g/cm 3 at a developed discharge stage. The radial expansion velocity of ∼10 4 cm/s measured at the 70-th nanosecond after the current start allows treating the dense core at a late stage in the form of a submicron heterogeneous structure from its liquid and slightly ionized gas phase.

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Prolonged plasma production at current-driven implosion of wire arrays on Angara-5-1 facility

Cited by 88 publications

References 7 publications

Wire ablation dynamics model and its application to imploding wire arrays of different geometries

Wire ablation dynamics model and its application to imploding wire arrays of different geometries

Characterisation of the current switch mechanism in two-stage wire array Z-pinches

Heterogeneous Plasma‐Producing Structures at Current Implosion of a Wire Array

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