Diagnostics of plasma channel for HIF transport

Ponce, D.; Niemann, Christoph; Yu, S.S.; Leemans, Wim; Fessenden, T.J.; Dahlbacka, G.; Sharp, W.M.; Taushwitz, A.

doi:10.1016/s0168-9002(01)00057-2

Cited by 8 publications

(2 citation statements)

References 6 publications

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“…One can apply an empirical model to explain the hydrodynamics based on a strong wave blast model. The strong blast model is similar to the ones studied in supernovae explosions [61]. In this instance we can have as well a second method in which to estimate the gas temperature.…”

Section: Phase Contrastmentioning

confidence: 89%

Plasma channel and Z-pinch dynamics for heavy ion transport

Ponce-Marquez¹

2002

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A self stabilized, free standing, z-pinch plasma channel has been proposed to deliver the high intensity heavy ion beam from the end of a driver to the fuel target in a heavy ion inertial fusion power plant. The z-pinch relaxes emittance and energy spread requirements requiring a lower cost driver. A z-pinch transport would reduce the number of beam entry port holes to the target chamber from over a hundred to four as compared to neutralized ballistic focusing thus reducing the driver hardware exposure to neutron flux. Experiments where a double pulse discharge technique is used, z-pinch plasma channels with enhanced stability are achieved. Typical parameters are 7 kV pre-pulse discharge and 30 kV main bank discharge with 50 kA of channel current in a 7 torr background gas atmosphere. This work is an experimental study of these plasma channels examining the relevant physics necessary to understand and model such plasmas. Laser diagnostics measured the dynamical properties 2 of neutrals and plasma. Schlieren and phase contrast techniques probe the pre-pulse gas dynamics and infrared interferometry and faraday effect polarimetry are used on the zpinch to study its electron density and current distribution. Stability and repeatability of the z-pinch depend on the initial conditions set by the pre-pulse. Results show that the z-pinch channel is wall stabilized by an on-axis gas density depression created by the pre-pulse through hydrodynamic expansion where the ratio of the initial gas density to the final gas density is > 10/1. The low on-axis density favors avalanching along the desired path for the main bank discharge. Pinch time is around 2 µs from the main bank discharge initiation with a FWHM of ≈ 2 cm. Results also show that typical main bank discharge plasma densities reach 10 17 cm −3 peak on axis for a 30 kV, 7 torr gas nitrogen discharge.Current rise time is limited by the circuit-channel inductance with the highest contribution to the impedance due to the plasma. There is no direct evidence of surface currents due to high frequency skin effects and magnetic field experiments indicate that > 70% of the current carried by the channel is enclosed within FWHM of the channel. Code-experiment benchmark comparisons show that simulations capture the main mechanisms of the channel evolution, but complete atomic models need to be incorporated.

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Section: Phase Contrastmentioning

confidence: 89%

Plasma channel and Z-pinch dynamics for heavy ion transport

Ponce-Marquez¹

2002

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“…Recent experiments have demonstrated robust and stable laser-created discharge channels carrying up to 55 kA and radii as small as 4 mm [42,43,44]. Magnetohydrodynamic (MHD) numerical modeling of these channels is under way [44].…”

Section: Assisted Pinched Transportmentioning

confidence: 99%

Impact of Beam Transport Method on Chamber and Driver Design for Heavy Ion Inertial Fusion Energy

Rose

Welch

Olson

et al. 2004

Fusion Science and Technology

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In heavy ion inertial fusion energy systems, intense beams of ions must be transported from the exit of the final focus magnet system through the target chamber to hit millimeter spot sizes on the target. In this paper, we examine three different modes of beam propagation: neutralized ballistic transport, assisted pinched transport, and self-pinched transport. The status of our understanding of these three modes is summarized, and the constraints imposed by beam propagation upon the chamber environment, as well as their compatibility with various chamber and target concepts, are considered. We conclude that, on the basis of our present understanding, there is a reasonable range of parameter space where beams can propagate in thick-liquid wall, wetted-wall, and dry-wall chambers.

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The heavy ion fusion program in the USA

Bangerter

2001

Nuclear Instruments and Methods in Physics Research Section A:

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The U.S. Department of Energy has established a new, larger inertial fusion energy program. To manage program growth, we have developed a new inertial fusion energy research and we have establishes a Virtual National Laboratory for Heavy Ion Fusion.There has been significant technical progress. Improvements in target design have reduced the predicted energy requirements by approximately a factor of two. There have also been important experiments on chamber dynamics and other inertial fusion technologies. The accelerator program has completed a number of small-scale experiments. Experiments with driver-scale beams are being designed --including experiments with driver-scale ion sources and injectors.Finally we are developing the technologies needed to build a major research facility known as the Integrated Research Experiment (IRE).

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Diagnostics of plasma channel for HIF transport

Cited by 8 publications

References 6 publications

Plasma channel and Z-pinch dynamics for heavy ion transport

Plasma channel and Z-pinch dynamics for heavy ion transport

Impact of Beam Transport Method on Chamber and Driver Design for Heavy Ion Inertial Fusion Energy

The heavy ion fusion program in the USA

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