Conceptual design of a 15-TW pulsed-power accelerator for high-energy-density—physics experiments

Spielman, R. B.; Froula, Dustin; Brent, G.; Campbell, E. M.; Reisman, D. B.; Savage, M. E.; Shoup, M. J.; Stygar, W. A.; Wisher, Matthew Louis

doi:10.1016/j.mre.2017.05.002

Cited by 32 publications

(12 citation statements)

References 17 publications

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“…If we only concentrate on the pulsed outputs, a certain number of normal modules in each level can guarantee the output performance to meet the expected requirement [7], which could be easily determined. However, the load-sharing mechanism results in a higher failure rate of each remaining normal modules after some modules have failed unexpectedly.…”

Section: Load-sharing Based Level Reliability Analysis With the Incrementioning

confidence: 99%

“…As a modified induction voltage adder (IVA) [4,5], the LTD also consists of several induction cavities called "LTD stages". A hierarchical and modular structure is adopted in the general design process of the LTD systems [6,7], which decreases the inherent complexity of the system and makes it possible to conduct module maintenance, recycling, and reconfiguration. Aimed to improve the output performance, many research projects focusing on LTD stages have been conducted.…”

Section: Introductionmentioning

confidence: 99%

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Reliability Modelling and Evaluation for LTD System Based on Load-Sharing Model

et al. 2019

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Based on power adding technology, the linear transformer driver (LTD) scheme is widely used to generate high-energy pulsed outputs and adopts a hierarchical and modular structure. Although robust design and fault analysis for basic components have been conducted recently, there is still a lack of enough reliability analysis studies of the whole system. Taking an actual LTD system as an object, this paper presents a system reliability model based on a load-sharing mechanism. A unified load-sharing rule structure is established and four typical rules corresponding to equal, linear, exponential, and local-equal relationships are discussed in detail while evaluating the impact of the load-sharing mechanism. Subsequently, simulation experiments are performed to illustrate the effects of different load-sharing rules as well as analyzing the system reliability in which we simultaneously propose a self-adaptive Monte Carlo simulation flow to achieve the sampling probability adjustment according to the random failure sequence. The simulation results can serve as a suggestion for further improvement of the system reliability. Moreover, the model framework and the simulation analysis method described here are universal and can be applied to evaluate the reliability of other LTD-based systems with tiny modifications.

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Section: Load-sharing Based Level Reliability Analysis With the Incrementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reliability Modelling and Evaluation for LTD System Based on Load-Sharing Model

et al. 2019

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“…Note that the origin of assumed prefires could be in the LTD cavity or in the trigger generator, we cannot distinguish between the two in these cases. Shots can be aborted while in the Trigger prefires (17) shots where the LTD fired before the command trigger and signals recorded by the data acquisition indicate synchronous closure of all switches. These conditions indicate that a prefire occurred in the trigger generator.…”

Section: Aborted Shots and System Malfunctionsmentioning

confidence: 99%

“…The High Energy Density Physics (HEDP) community is proposing to build a next-generation pulsed-power accelerator with peak electrical output power in the range of 300 TW to 1,000 TW [1][2][3][4][5][6]. The prime power source of such a machine may consist of a system of linear transformer drivers (LTDs) [7][8][9][10][11][12][13][14][15][16][17][18] fast Marx generators (FMGs) [7,9,[19][20][21][22] or impedance-matched Marx generators (IMGs) [18,23,24]. The pulsed power community has been developing LTD technology for 20 years on various single-cavity experiments [16,[25][26][27][28][29][30][31][32][33][34][35][36][37], multicavity (single "module") experiments [14,27,32,35,[38][39]…”

Section: Introductionmentioning

confidence: 99%

100 GW linear transformer driver cavity: Design, simulations, and performance

Douglass¹,

Hutsel²,

Leckbee³

et al. 2018

Phys. Rev. Accel. Beams

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Herein we present details of the design, simulation, and performance of a 100-GW linear transformer driver (LTD) cavity at Sandia National Laboratories. The cavity consists of 20 "bricks." Each brick is comprised of two 80 nF, 100 kV capacitors connected electrically in series with a custom, 200 kV, threeelectrode, field-distortion gas switch. The brick capacitors are bipolar charged to AE100 kV for a total switch voltage of 200 kV. Typical brick circuit parameters are 40 nF capacitance (two 80 nF capacitors in series) and 160 nH inductance. The switch electrodes are fabricated from a WCu alloy and are operated with breathable air. Over the course of 6,556 shots the cavity generated a peak electrical current and power of 1.03 MA (AE1.8%) and 106 GW (AE3.1%). Experimental results are consistent (to within uncertainties) with circuit simulations for normal operation, and expected failure modes including prefire and latefire events. New features of this development that are reported here in detail include: (1) 100 ns, 1 MA, 100-GW output from a 2.2 m diameter LTD into a 0.1 Ω load, (2) high-impedance solid charging resistors that are optimized for this application, and (3) evaluation of maintenance-free trigger circuits using capacitive coupling and inductive isolation.

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“…The LTD concept was pioneered by Koval'chuk et al [7] and has received increasing attention in recent years [8][9][10][11], including a recent review on the history of LTD development [12]. Several LTD machines are operational or under development in the USA [13][14][15][16], Europe [17,18], Russia [19,20], and Asia [21,22].…”

Section: Introductionmentioning

confidence: 99%

MA-class linear transformer driver for Z -pinch research

Conti

Valenzuela

Fadeev

et al. 2020

Phys. Rev. Accel. Beams

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A linear transformer driver (LTD) generator capable of delivering up to 0.9 MA current pulses with 160 ns rise time has been assembled and commissioned at University of California San Diego. The machine is an upgrade of the LTD-III pulser from Sandia National Laboratories, consisting of 40 capacitors and 20 spark gap switches, arranged in a 20-brick configuration. The driver was modified with the addition of a new trigger system, active premagnetization of the inductive cores, a vacuum chamber with multiple diagnostic ports, and a vacuum power feed to couple the driver to plasma loads. The new machine is called compact experimental system for Z-pinch and ablation research (CESZAR). The driver has a maximum bipolar charge voltage of AE100 kV, but for reliability and testing, and to reduce the risk of damage to components, the machine was operated at AE60 kV, producing 550 kA peak currents with a rise time of 170 ns on a 3.5 nH short circuit. While the peak current is scaled down due to the reduced charge voltage, the pulse shape and circuit parameters are close to the results of the cavity and power feed models but suggest a slightly higher inductance than predicted. The machine was then used to drive wire array Z-pinch and gas puff Z-pinch experiments as initial dynamic plasma loads. The evolution of the wire array Z pinch is consistent with the general knowledge of this kind of experiment, featuring wire ablation and stagnation of the precursor plasma on axis. The gas puff Z pinches were configured as a single, hollow argon gas shell, in preparation for more structured gas puff targets such as multispecies, multishell implosions. The implosion dynamics agree generally with 1D magnetohydrodynamics simulation results, but large zippering and magneto-Rayleigh-Taylor instabilities are observed. The CESZAR load region was designed to accommodate many load types to be driven by the machine, which makes it a versatile platform for studying Z-pinch plasmas. The completion of the CESZAR driver allows plasma experiments on energy coupling from LTD machines to plasma loads, instability mitigation techniques and magnetic field distributions in Z pinches, and interface dynamics in multispecies implosions.

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Conceptual design of a 15-TW pulsed-power accelerator for high-energy-density—physics experiments

Cited by 32 publications

References 17 publications

Reliability Modelling and Evaluation for LTD System Based on Load-Sharing Model

Reliability Modelling and Evaluation for LTD System Based on Load-Sharing Model

100 GW linear transformer driver cavity: Design, simulations, and performance

MA-class linear transformer driver for Z -pinch research

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