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High-gain magnetized liner inertial fusion (MagLIF) is a possible way to realize fusion. To investigate electrothermal effects on the transport of magnetic flux and thermal flux in MagLIF, this study has developed a resistive magnetohydrodynamics (MHD) module including an axial magnetic field using the code MULTI-IFE. MagLIF driven by a peak current of 60 MA releases 1080 MJ of fusion energy for a 1-cm-long liner, corresponding to an energy gain of approximately 180. The magnetic field is decompressed by electrothermal effects owing to the great temperature gradient in the fuel. This papers shows that a Nernst flux limiter of between 0.1 and 0.3 prevents the Nernst velocity from significantly decompressing the axial magnetic field and achieving a relative high yield. Compared with that of a simple gas target, the magnetic flux loss in the high-gain MagLIF target can be reduced from 70% to 30% owing to the magnetic insulation in the cryogenic deuterium-tritium. Most of the cryogenic DT layer in a high-gain MagLIF target is burned, resulting in a significant increase in the fusion yield.

Summarization: This article addresses key features for the implementation of low current pulsed power plasma devices for the study of matter dynamics from the solid to the plasma phase. The renewed interest in such low current plasma devices lies in the need to investigate methods for the mitigation of prompt seeding mechanisms for the generation of plasma instabilities. The low current when driven into thick wires (skin effect mode) allows for the simultaneous existence of all phases of matter from solid to plasma. Such studies are important for the concept of inertial confinement fusion where the mitigation of the instability seeding mechanisms arising from the very early moments within the target's heating is of crucial importance. Similarly, in the magnetized liner inertial fusion concept it is an open question as to how much surface non-uniformity correlates with the magneto-Rayleigh-Taylor instability, which develops during the implosion. This study presents experimental and simulation results, which demonstrate that the use of low current pulsed power devices in conjunction with appropriate diagnostics can be important for studying seeding mechanisms for the imminent generation of plasma instabilities in future research. Παρουσιάστηκε στο: Plasma Physics and Controlled Fusion

Ignition conditions in axially magnetized cylindrical targets are investigated by examining the thermal balance of assembled DT fuel configurations at stagnation. Special care is taken to adequately evaluate the energy fraction of 3.5 MeV alpha particles deposited in magnetized DT cylinders. A detailed analysis of the ignition boundaries in the ρR,T parametric plane is presented. It is shown that the fuel magnetization allows a significant reduction of the ρR ignition threshold only when the condition BR 6 × 105G cm is fulfilled (B is the magnetic field strength and R is the fuel radius).

Several magnetized liner inertial fusion (MagLIF) experiments have been conducted on the Z accelerator at Sandia National Laboratories since late 2013. Measurements of the primary DD (2.45 MeV) neutrons for these experiments suggest that the neutron production is thermonuclear. Primary DD yields up to 3e12 with ion temperatures ~2-3 keV have been achieved. Measurements of the secondary DT (14 MeV) neutrons indicate that the fuel is significantly magnetized. Measurements of down-scattered neutrons from the beryllium liner suggest ρRliner ~ 1g/cm2. Neutron bang times, estimated from neutron time-of-flight (nTOF) measurements, coincide with peak x-ray production. Furthermore, plans to improve and expand the Z neutron diagnostic suite include neutron burn-history diagnostics, increased sensitivity and higher precision nTOF detectors, and neutron recoil-based yield and spectral measurements.

A simple, zero-dimensional model describing the temporal behaviour of an imploding-shell, magnetized fuel inertial confinement fusion target is formulated. The model includes effects not normally considered in inertial confinement fusion such as magnetic back-pressure on the imploding shell, magnetic reduction of thermal conductivity, magnetic diffusion, and Ohmic heating. The model is simple enough to permit a survey of the parameter space available for magnetized fuel by computing the behaviour of thousands of targets. The survey predicts the existence of a totally new region in parameter space where significant thermonuclear fuel burn-up can occur. The new region is characterized by very low fuel densities, very low implosion velocities, and,most important, driver requirements reduced by several orders of magnitude, suggesting that "break-even" experiments may be possible with existing inertial confinement fusion drivers. The computed results are in reasonable agreement with more complete two-dimensional magnetohydrodynamic simulations.