Quantifying ionization in hot dense plasmas

Physical Review E American Physical Society 109 (2024) L023201

Authors:

Thomas Gawne, Sam Vinko, Justin Wark

Abstract:

Ionization is a problematic quantity in that it does not have a well-defined thermodynamic definition, yet it is a key parameter within plasma modelling. One still therefore aims to find a consistent and unambiguous definition for the ionization state. Within this context we present finite-temperature density functional theory calculations of the ionization state of carbon in CH plasmas using two potential definitions: one based on counting the number of continuum electrons, and another based on the optical conductivity. Differences of up to 10% are observed between the two methods. However, including “Pauli forbidden” transitions in the conductivity reproduces the counting definition, suggesting such transitions are important to evaluate the ionization state.

Multi-GeV wakefield acceleration in a plasma-modulated plasma accelerator

Physical Review E American Physical Society (APS) 109:2 (2024) 025206

Authors:

JJ van de Wetering, SM Hooker, R Walczak

Energy gain of wetted-foam implosions with auxiliary heating for inertial fusion studies

Plasma Physics and Controlled Fusion IOP Publishing 66:2 (2024) 025005

Authors:

RW Paddock, TS Li, E Kim, JJ Lee, H Martin, RT Ruskov, S Hughes, SJ Rose, CD Murphy, RHH Scott, R Bingham, W Garbett, VV Elisseev, BM Haines, AB Zylstra, EM Campbell, CA Thomas, T Goffrey, TD Arber, R Aboushelbaya, MW Von der Leyen, RHW Wang, AA James, I Ouatu, R Timmis, S Howard, E Atonga, PA Norreys

Classical Larmor formula through the Unruh effect for uniformly accelerated electrons

Physical Review D: Particles, Fields, Gravitation and Cosmology American Physical Society 109 (2024) 024044

Abstract:

We investigate the connection between the classical Larmor formula and the quantum Unruh effect by computing the emitted power by a uniformly accelerated charged particle and its angular distribution in the co-accelerated frame. We consider a classical particle accelerated with non-zero charge only for a finite period and then take the infinite-time limit after removing the effects due to the initial charging and final discharging processes. We show that the result found for the interaction rates agrees with previous studies in which the period of acceleration with non-zero charge was taken to be infinite from the beginning. We also show that the power and angular distribution of emission, which is attributed either to the emission or absorption of a Rindler photon in the co-accelerated frame, is given by the Larmor formula, confirming that, at tree level, it is necessary to take into account the Unruh effect in order to reproduce the classical Larmor radiation formula in the coaccelerated frame.

Quantum effects on dynamic structure factors in dense magnetized plasmas

Physical Review E: Statistical, Nonlinear, and Soft Matter Physics American Physical Society 6:1 (2024) 013089

Authors:

Tushar Mondal, Gianluca Gregori

Abstract:

We extend the classical magnetohydrodynamics formalism to include nonlocal quantum behavior via the phenomenological Bohm potential. We then solve the quantum magnetohydrodynamics equations to obtain a new analytical form of the dynamic structure factor (DSF), a fundamental quantity linking theory and experiments. Our results show that the three-peak structure—one central Rayleigh peak and two Brillouin peaks—of the DSF arising from quantum hydrodynamic fluctuations becomes (in general) a five-peak structure—one central Rayleigh peak and two pairs of peaks associated with fast and slow magnetosonic waves. The Bohm contribution influences the positions and characteristics (height, width, and intensity) of the peaks by introducing three significant modifications: (a) an increase in effective thermal pressure, (b) a reduction in the adiabatic index, and (c) an enhancement of effective thermal diffusivity. The multiple DSF peaks enable concurrent measurements of diverse plasma properties, transport coefficients, and thermodynamic parameters in magnetized dense plasmas. The potential for experimental validation of our theory looms large, particularly through future experiments conducted at state-of-the-art laser facilities.