Characterization of a self-magnetic-pinched diode

Hinshelwood, D.D.; Cooperstein, G.; Mosher, D.; Ponce, D.; Strasburg, Sean; Swanekamp, S.B.; Stephanakis, S. J.; Weber, B.V.; Young, F.C.; Critchley, A.; Crotch, I.; Threadgold, J.

doi:10.1109/tps.2005.845305

Cited by 21 publications

(6 citation statements)

References 12 publications

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“…This represents the usable current, i.e., the current that can be readily coupled to the typical radiographic diodes such as the negative-polarity rod-pinch [25] and self-magnetic pinch diodes [26]- [28]. The individual points in Fig.…”

Section: Bound-current Estimationmentioning

confidence: 99%

Design, Simulation, and Fault Analysis of a 6.5-MV LTD for Flash X-Ray Radiography

Leckbee

Maenchen

Johnson

et al. 2006

IEEE Trans. Plasma Sci.

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The design of a 6.5-MV linear transformer driver (LTD) for flash-radiography experiments is presented. The design is based on a previously tested 1-MV LTD and is predicted to be capable of producing diode voltages of 6.5 MV for a 50-Ω radiographic-diode load. Several fault modes are identified, and circuit simulations are used to determine their effect on the output pulse and other components. For all the identified fault modes, the peak load voltage is reduced by less than 5%.Index Terms-Circuit simulation, electron accelerator, pulse power systems, radiography, X-ray applications.

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Section: Bound-current Estimationmentioning

confidence: 99%

Design, Simulation, and Fault Analysis of a 6.5-MV LTD for Flash X-Ray Radiography

Leckbee

Maenchen

Johnson

et al. 2006

IEEE Trans. Plasma Sci.

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“…The self-magnetic-pinch (SMP) diode [1][2][3][4] is being developed as an intense electron beam source for pulsedpower-driven x-ray radiography. The diode is composed of a thin cylindrical cathode with a hollow, rounded tip, as illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…It has been observed, however, that the SMP diode current increases beyond predictions for the critical current, resulting in a decreasing diode impedance [4,7,8]. The proposed mechanism for the impedance reduction is electrode plasma expansion into the A-K gap [3,9].…”

Section: Introductionmentioning

confidence: 99%

Anode plasma dynamics in the self-magnetic-pinch diode

Bruner

Welch

Hahn

et al. 2011

Phys. Rev. ST Accel. Beams

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The self-magnetic-pinch diode is being developed as an intense electron beam source for pulsed-powerdriven x-ray radiography. In high-power operation, the beam electrons desorb contaminants from the anode surface from which positive ions are drawn to the cathode. The counterstreaming electrons and ions establish an equilibrium current. It has long been recognized, however, that expanding electrode plasmas can disrupt this equilibrium and cause rapid reduction of the diode impedance and the radiation pulse. Recently developed numerical techniques, which enable simultaneous modeling of particle currents with 10 13 cm À3 densities to plasmas of near solid density, are applied to a model of the self-magnetic-pinch diode which includes the formation and evolution of anode surface plasmas. Two mechanisms are shown to cause rapid impedance loss, anode plasma expansion into the anode-cathode (A-K) gap, and increased ion space-charge near the cathode surface. The former mechanism dominates for shorter A-K gaps, while the latter dominates for longer gaps. Model results qualitatively reproduce the time-dependent impedances measured for this diode.

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“…The self-magnetic-pinch (SMP) diode [1][2][3][4][5] is being developed as an intense electron beam source for pulsed-powerdriven x-ray radiography. The electron beam is generated via explosive field emission from the cathode 6 through a process of surface breakdown and formation of a cathode plasma.…”

Section: Introductionmentioning

confidence: 99%

The impact of plasma dynamics on the self-magnetic-pinch diode impedance

et al. 2015

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The self-magnetic-pinch diode is being developed as an intense electron beam source for pulsedpower-driven x-ray radiography. The basic operation of this diode has long been understood in the context of pinched diodes, including the dynamic effect that the diode impedance decreases during the pulse due to electrode plasma formation and expansion. Experiments being conducted at Sandia National Laboratories' RITS-6 accelerator are helping to characterize these plasmas using timeresolved and time-integrated camera systems in the x-ray and visible. These diagnostics are analyzed in conjunction with particle-in-cell simulations of anode plasma formation and evolution. The results confirm the long-standing theory of critical-current operation with the addition of a time-dependent anode-cathode gap length. The results may suggest that anomalous impedance collapse is driven by increased plasma radial drift, leading to larger-than-average ion v r Â B h acceleration into the gap. V C 2015 AIP Publishing LLC. [http://dx.

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Characterization of a self-magnetic-pinched diode

Cited by 21 publications

References 12 publications

Design, Simulation, and Fault Analysis of a 6.5-MV LTD for Flash X-Ray Radiography

Design, Simulation, and Fault Analysis of a 6.5-MV LTD for Flash X-Ray Radiography

Anode plasma dynamics in the self-magnetic-pinch diode

The impact of plasma dynamics on the self-magnetic-pinch diode impedance

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