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Kritcher, Andrea

Publications and source records attributed to Kritcher, Andrea.

6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Roadmap for warm dense matter physics

This roadmap presents the state-of-the-art, current challenges and near future developments anticipated in the thriving field of warm dense matter physics. Originating from strongly coupled plasma physics, high pressure physics and high energy density science, the warm dense matter physics community has recently taken a giant leap forward. This is due to spectacular developments in laser technology, diagnostic capabilities, and computer simulation techniques. Only in the last decade has it become possible to perform accurate enough simulations \& experiments to truly verify theoretical results as well as to reliably design experiments based on predictions. Consequently, this roadmap discusses recent developments and contemporary challenges that are faced by theoretical methods, and experimental techniques needed to create and diagnose warm dense matter. A large part of this roadmap is dedicated to specific warm dense matter systems and applications in astrophysics, inertial confinement fusion and novel material synthesis.

FOS: Physical sciences↗
DOE OSTI2022

Hydroscaling indirect-drive implosions on the National Ignition Facility

A goal of the laser-based National Ignition Facility (NIF) is to increase the liberated fusion energy “yield” in inertial confinement fusion experiments well past the ignition threshold and the input laser energy. One method of increasing the yield, hydrodynamic scaling of current experiments, does not rely on improving compression or implosion velocity, but rather increases the scale of the implosion to increase hotspot areal density and confinement time. Indirect-drive (Hohlraum driven) implosions carried out at two target sizes, 12.5% apart, have validated hydroscaling expectations. Moreover, extending comparisons to the best-performing implosions at five different capsule sizes shows that their performance also agrees well with hydroscaling expectations even though not direct hydroscales of one another. In the future, by switching to a reduced loss Hohlraum geometry, simulations indicate that we can drive 20% larger-scale implosions within the current power and energy limitations on the NIF. Finally, at the demonstrated compression and velocity of these smaller-scale implosions, these 1.2× hydroscaled implosions should put us well past the ignition threshold.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Comparison of ablators for the polar direct drive exploding pusher platform

We examine the performance of pure boron, boron carbide, high density carbon, and boron nitride ablators in the polar direct drive exploding pusher (PDXP) platform. The platform uses the polar direct drive conguration at the National Ignition Facility to drive high ion temperatures in a room temperature capsule and has potential applications for plasma physics studies and as a neutron source. The higher tensile strength of these materials compared to plastic enables a thinner ablator to support higher gas pressures, which could help optimize its performance for plasma physics experiments, while ablators containing boron enable the possiblity of collecting addtional data to constrain models of the platform. Applying recently developed and experimentally validated equation of state models for the boron materials, we examine the performance of these materials as ablators in 2D simulations, with particular focus on changes to the ablator and gas areal density, as well as the predicted symmetry of the inherently 2D implosion.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Integrated Design of a Robust System for Inertial Fusion Energy

For inertial fusion energy (IFE) to be successful, designs need to work robustly including both target physics and engineering considerations. For a power plant to be reliable and have a high operating capacity factor, the integrated design of the target, driver, target fabrication, target injection system, and chamber all need to work together in way that is robust and repeatable to expected variations. One of the lesson’s learned from our experience at NIF is that designs that are sensitive have not performed as expected – even in single shot mode. The lesson’s learned from NIF should be folded into creating integrated designs for IFE and for evaluating the tradeoffs between the different parts of the IFE system. To do so, we propose using the NIF 1.3 MJ yield shot/design (N210808) as a starting point of a study of the feasibility of indirect drive designs for IFE. If the hohlraum inefficiency precludes indirect drive, the study would include direct drive or fast ignition versions of this design.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2019

New Design for Low-Mode Asymmetry Mitigation in Inertial Confinement Fusion Implosions

Radiation flux symmetry in laser-irradiated hohlraum environments is difficult to model and control and relies on the details of plasma evolution and laser energy deposition in the harsh plasma-filled hohlraum over the duration of the laser pulse. This study presents a conceptual design and assesses the feasibility of using lasers to create a drive where the implosion symmetry relies mainly on radiation transport. In this design lasers irradiate the ends of a capsule containing hohlraum that are shielded from the view of the capsule. This configuration enables the use of frequency doubled light that has a higher power and energy threshold for the current capability of NIF, up to 670TW and ~3.5 MJ. We estimate, using VISRAD benchmarked against HYDRA calculations, that the same drive conditions that are currently being achieved in hybridE experiments at the NIF 270-290 at the equator can be reached in this new geometry and large 6.4 mm diameter hohlraums. The radiation drive asymmetries in this design can be mitigated by shimming the capsule ablator thickness or through tailoring the shape of the shielding to the laser spots.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗