High Current Fast 100-NS LTD Driver Development in Sandia Laboratory

Mazarakisaa, M.G.; Fowler, William; Long, F. W.; McDaniel, D. H.; Olson, Craig; Rogowski, S.; Sharpe, R.A.; Struve, K. W.; Kim, A.A.

doi:10.1109/ppc.2005.300657

Cited by 19 publications

(10 citation statements)

References 5 publications

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“…The model generalizes that proposed by Mazarakis and colleagues in Refs. [11,25] by including a parallel resistance to account for energy loss to the inductive magnetic cores of the LTD cavities. Considerably more accurate LTD circuit models are proposed by Kim and colleagues in Ref.…”

Section: Appendix B: Optimum Output Impedance Of the Internal Transmimentioning

confidence: 99%

“…For such an IVA, part of the MITL is located within, and is concentric to, the IVA's cavities. Following this precedent, Kovalchuk et al [1,5,12], Mazarakis et al [6,8,11,25,29,31,32,36], Kim et al [15,18,33], Rose et al [17,27], Leckbee et al [22,24,28], Olson [26], and Gomez et al [35] developed designs of LTD modules that drive an internal MITL. Such modules have been considered for zpinch-physics [1,5,8,11,25,29,[31][32][33]35,36], x-rayradiography [6,11,15,17,18,22,24,27,28], excimer-laser [12], and inertial-confinement-fusion (ICF) [25,26,29,31] applications.…”

Section: Introductionmentioning

confidence: 99%

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Shaping the output pulse of a linear-transformer-driver module

Stygar

Fowler

LeChien

et al. 2009

Phys. Rev. ST Accel. Beams

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We demonstrate that a wide variety of current-pulse shapes can be generated using a linear-transformerdriver (LTD) module that drives an internal water-insulated transmission line. The shapes are produced by varying the timing and initial charge voltage of each of the module's cavities. The LTD-driven accelerator architecture outlined in [Phys. Rev. ST Accel. Beams 10, 030401 (2007)] provides additional pulseshaping flexibility by allowing the modules that drive the accelerator to be triggered at different times. The module output pulses would be combined and symmetrized by water-insulated radial-transmission-line impedance transformers [Phys. Rev. ST Accel.

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Section: Appendix B: Optimum Output Impedance Of the Internal Transmimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Shaping the output pulse of a linear-transformer-driver module

Stygar

Fowler

LeChien

et al. 2009

Phys. Rev. ST Accel. Beams

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“…The LTD driver LDRD experimental research was concentrated this year on two aspects; first to study the repetition rate capabilities of the LTD [52], [53], [54] cavities and second to study how a number of cavities behave and add their energy, power and voltage output in a voltage adder configuration assembly.…”

Section: Linear Transformer Driver (Ltd) (M Mazarakis Snl)mentioning

confidence: 99%

“…A 60 MA, 7 MV, ~100-ns driver for a Z-pinch Inertial Fusion Energy (Z-IFE) power plant has been proposed [54]. In this summary we address the transition region between the 70 Linear Transformer Driver (LTD) modules and the center Recyclable Transmission Line (RTL) load section, which convolves from the coaxial vacuum Magnetically Insulated Transmission Lines (MITL) to a parallel tri-plate and then a biplate disk feed.…”

Section: Driver Transition Geometries and Inductance Considerations Lmentioning

confidence: 99%

Recyclable transmission line (RTL) and linear transformer driver (LTD) development for Z-pinch inertial fusion energy (Z-IFE) and high yield.

Sharpe¹,

Kingsep

Smith³

et al. 2007

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Z-Pinch Inertial Fusion Energy (Z-IFE) complements and extends the single-shot zpinch fusion program on Z to a repetitive, high-yield, power plant scenario that can be used for the production of electricity, transmutation of nuclear waste, and hydrogen production, all with no CO 2 production and no long-lived radioactive nuclear waste. The Z-IFE concept uses a Linear Transformer Driver (LTD) accelerator, and a Recyclable Transmission Line (RTL) to connect the LTD driver to a high-yield fusion target inside a thick-liquid-wall power plant chamber.Results of RTL and LTD research are reported here, that include: (1) The key physics issues for RTLs involve the power flow at the high linear current densities that occur near the target (up to 5 MA/cm). These issues include surface heating, melting, ablation, plasma formation, electron flow, magnetic insulation, conductivity changes, magnetic field diffusion changes, possible ion flow, and RTL mass motion. These issues are studied theoretically, computationally (with the ALEGRA and LSP codes), and 4 will work at 5 MA/cm or higher, with anode-cathode gaps as small as 2 mm. (2) An RTL misalignment sensitivity study has been performed using a 3D circuit model. Results show very small load current variations for significant RTL misalignments. (3) The key structural issues for RTLs involve optimizing the RTL strength (varying shape, ribs, etc.) while minimizing the RTL mass. Optimization studies show RTL mass reductions by factors of three or more. (4) Fabrication and pressure testing of Z-PoP (Proof-ofPrinciple) size RTLs are successfully reported here. (5) Modeling of the effect of initial RTL imperfections on the buckling pressure has been performed. Results show that the curved RTL offers a much greater buckling pressure as well as less sensitivity to imperfections than three other RTL designs. (6) Repetitive operation of a 0.5 MA, 100 kV, 100 ns, LTD cavity with gas purging between shots and automated operation is demonstrated at the SNL Z-IFE LTD laboratory with rep-rates up to 10.3 seconds between shots (this is essentially at the goal of 10 seconds for Z-IFE). (7) A single LTD switch at Tomsk was fired repetitively every 12 seconds for 36,000 shots with no failures. Present results from all of these power flow studies validate the whole LTD/RTL concept for single-shot ICF high yield, and for repetitive-shot IFE.

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“…The switches operate with compressed air instead of sulfur hexafluoride (SF6), reducing the operational costs and eliminating asphyxiation hazards [6]. In addition, LTDs theoretically can offer a repetition rate of up to 10 Hz, compared to Marx banks which require a long period of time to charge the capacitors [7].…”

Section: Iintroductionmentioning

confidence: 99%

Development of a 200-kV Test Stand and Experimental Study of Optical Triggering Methods for LTD Switches

Sullivan

Kovaleski

Hutsel

et al. 2008

2008 IEEE International Power Modulators and High-Voltage Conference

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A 200-kV test stand is being developed at the University of Missouri to examine optical triggering techniques for LTD switches. Two capacitors, separated by an optically triggered switch, are DC charged to ±100-kV. The switch will be triggered by a pulse from an Nd:YAG laser at 266, 532, and 1064-nm wavelengths. The goal of the study is to find methods to reduce the optical energy required to trigger the switch while minimizing runtime and jitter. To reduce laser energy, several methods will be explored. One method is to identify candidate materials based on their respective work functions and apply them to the switch cathode. Laser light will be directed onto the target materials with intensity below the ablation threshold, liberating electrons. Another method is to create a laser spark created in the mid-gap of the switch while manipulating length, position and orientation through control of laser power, focusing lenses, lens positions, insulating gas composition and photon energy. Findings will be used in designing of future LTD switches and triggering systems.

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High Current Fast 100-NS LTD Driver Development in Sandia Laboratory

Cited by 19 publications

References 5 publications

Shaping the output pulse of a linear-transformer-driver module

Shaping the output pulse of a linear-transformer-driver module

Recyclable transmission line (RTL) and linear transformer driver (LTD) development for Z-pinch inertial fusion energy (Z-IFE) and high yield.

Development of a 200-kV Test Stand and Experimental Study of Optical Triggering Methods for LTD Switches

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