Samuel Langendorf

Plasma-jet-driven magneto-inertial fusion is an alternative approach to controlled nuclear fusion, which aims to utilize a line-replaceable dense plasma liner as a repetitive spherical compression driver. In this experiment, first measurements of the formation of a spherical argon plasma liner formed from 36 discrete pulsed plasma jets are obtained on the Plasma Liner Experiment. Properties including liner uniformity and morphology, plasma density, temperature, and ram pressure are assessed as a function of time throughout the implosion process and indicate an apparent transition from initial kinetic inter-jet interpenetration to collisional regime near stagnation times, in accordance with theoretical expectation. A lack of primary shock structures between adjacent jets during flight implies that arbitrarily smooth liners may be formed by way of corresponding improvements in jet parameters and control. The measurements facilitate the benchmarking of computational models and understanding the scaling of plasma liners toward fusion-relevant energy density.

This paper introduces a novel approach for automated high-throughput estimation of plasma temperature and density using atomic emission spectroscopy, integrating Bayesian inference with sophisticated physical models. We provide an in-depth examination of Bayesian methods applied to the complexities of plasma diagnostics, supported by a robust framework of physical and measurement models. Our methodology is demonstrated using experimental observations in the field of magneto-inertial fusion, focusing on individual and sequential shot analyses of the Plasma Liner Experiment at LANL. The results demonstrate the effectiveness of our approach in enhancing the accuracy and reliability of plasma parameter estimation and in using the analysis to reveal the deep hidden structure in the data. This study not only offers a new perspective of plasma analysis but also paves the way for further research and applications in nuclear instrumentation and related domains.

The Plasma Liner eXperiment (PLX) recently demonstrated formation of an imploding plasma liner via the merging of 36 discrete jets. Magnetized targets have been routinely formed by head-on collision of two deuterium jets magnetized by the interaction with fields from external solenoids. These jets are formed by coaxial pulsed plasma accelerators. Our three-dimensional simulation tool SPFMax has been validated against these experimental data, providing confidence to perform integrated simulations including plasma liner formation, magnetized target formation, and target compression. SPFMax is used to model the effects of plasma jet initial conditions on fusion yield in a reactor relevant parameter space. The fusion parameter space is defined by the Lindl-Widner diagram. Critical parameters such as hot spot temperature, hot spot areal density and magnetic field are used to determine potential pathways to achieve self-ignition for reactor scale fusion energies.

The Plasma Liner Experiment (PLX) at Los Alamos National Laboratory is studying plasma-jet driven magneto-inertial fusion (PJMIF), an innovative fusion approach in which a magnetized target plasma is compressed and heated by a spherically imploding plasma liner. We report on experimental efforts towards target formation experiments using colliding magnetized plasma jets, formed by coaxial plasma guns with applied field. In the collision of high-beta magnetized jets, we observe aspects of collisional and collisionless plasma dynamics during the jet collision and stagnation, informed by Doppler ion spectroscopy measurements of ion bulk flow and thermalization. Implications for future integrated liner-on-target compression experiments are presented. We also describe a range of kinetic and fluid modeling efforts studying both the near-term experimental scale as well as scaling of the broader PJMIF concept.

Alfven waves are low-frequency, transverse magnetic tension waves that travel along magnetic field lines and can be excited in any electrically conducting fluid permeated by a magnetic field. They are commonly found in space, responsible for many well-known features, such as heating of the Sun's outer atmosphere, acceleration of solar wind, and aurora formed in high-latitude regions of the Earth. In this work, we present observations of standing Alfven waves excited by injecting compact toroid (CT) plasmas into a static Helmholtz magnetic field at the Big Red Ball (BRB) Facility at Wisconsin Plasma Physics Laboratory (WIPPL). The CT plasmas are injected in parallel with the magnetic field. The topology of the magnetic field in the standing Alfven waves is characterized using a 3-axis Bdot probe array.

The Plasma Liner Experiment (PLX) group at LANL is studying the formation and properties of spherically imploding plasma liners at supersonic speeds, used in the novel plasma-jet-driven magneto-inertial fusion (PJMIF) concept. At PLX, a set of 36 coaxial plasma guns over the spherical chamber each deliver a plasma jet towards the center, merging into a liner to compress a low-Z plasma target. Recent upgrades have enabled a reduction in jet-to-jet speed variability and therefore improved liner uniformity towards that required for adequate heating and confinement of the target. We present preliminary results of the present campaign on PLX which aims to study the temporal and spatial evolution of characteristics of the plasma liner and its formation, without target injection. Liner electron temperature will be studied using a multi-chord visible light spectroscopy system, line-integrated electron density using a multi-chord interferometer, and a wide-view multi-camera array (WMCA) for determining velocities of all individual jets, as well as visually assessing liner merging characteristics.