19–23 Sept 2022
Frascati
Europe/Rome timezone

Laser-driven quasi-static magnetic fields for magnetized high energy-density experiments

Not scheduled
20m
Bruno Brunelli Hall (Frascati)

Bruno Brunelli Hall

Frascati

via E. Fermi, 45, 00040 Frascati
oral Session 5

Speaker

CHRISTOS VLACHOS (University of Bordeaux)

Description

The use of seed magnetic-fields (B-fields) in laser-driven target-compression experiments may lead to > 10 kT B-fields across the compressed core due to advection of the in-flow plasma. B-fields exceeding 10 kT are promising for magneto-inertial fusion since they reduce electron thermal conduction perpendicular to the field lines and may even increase alpha-particle energy deposition in the hot spot. Studying the formation of these compressed B-fields may also improve our understanding of extreme plasma magnetization phenomena relevant to astrophysics or extended magnetohydrodynamics.

In order to reach compressed B-fields exceeding 10 kT, one important challenge is to generate strong seed B-fields on major laser facilities. Where external pulsed power hardware is not available, we can use laser-driven coil (LDC) targets to supply a multi-tesla quasi-static field. These targets allow easy access for diagnostics and do not produce a significant quantity of debris.

We have tested LDCs on several different nanosecond laser facilities under laser drive conditions relevant to the Laser MegaJoule (LMJ). The goal was to predict the B-fields that might be achieved on LMJ by benchmarking a laser-driven diode model of B-field generation [1]. At the LULI2000 and OMEGA facilities we used comparable laser intensities, ~1015 -1016 W/cm2, at 1.06µm and 0.35µm wavelengths respectively. We generated discharge currents of ~20 kA and ~8 kA yielding B-fields of ~50 T and ~6 T respectively, with targets of different size (and inductance).

Where possible, magnetic fields were measured using proton deflectometry directed along two axes of the target. Comparing our experimental deflectograms with proton tracking simulations enables us to identify various deflection features that can be linked to the looping current or static charging of the coil’s wire surface. Measured discharge currents are broadly consistent with predictions from our model for all the experimentally tested conditions, which give grounds for the successful use of LDCs on large-scale facilities like LMJ [2].

Author

CHRISTOS VLACHOS (University of Bordeaux)

Co-authors

Dr Bruno Albertazzi (LULI, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex, France) Annette Calisti (Aix-Marseille University) Matthieu Bailly-Grandvaux (University of California) Farhat Beg (University of California) Philip Bradford (Universite de Bordeaux) Xavier Vaisseau (CEA, DAM) Jacob Saret (University of California) Ms Valeria Ospina-Bohorquez (University of Bordeaux) Marco Gigosos (Universidad de Valladolid) Prof. Robert Fedosejevs (Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada ) Christopher Walsh (Lawrence Livermore National Laboratory) Tadeusz Pisarczyk (Institute of Plasma Physics and Laser Microfusion) Ms Channprit Kaur (Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada ) Dr Laurent Gremillet (CEA, DAM, DIF, F-91297 Arpajon, France) Tomasz Chodukowski (Institute of Plasma Physics and Laser Microfusion) Jan Dostal (Institute of Plasma Physics, Czech Academy of Sciences, 182 00 Prague, Czech Republic) Christopher McGuffey (General Atomics, San Diego) Francisco Suzuki-Vidal (Imperial College London) Prof. Luca Volpe (C.L.P.U. (Centro de Láseres Pulsados), Salamanca, Spain) Joao Santos (Universite de Bordeaux) Gabriel Perez-Callejo (Universidad de Valladolid) Sandrine Ferri (Aix-Marseille University) Michael Ehret (CLPU) Roman Dudzak (Institute of Plasma Physics, CAS, Prague, Czech Republic) Ricardo Florido (Universidad de Las Palmas de Gran Canaria) Mr Soussan Eitan (LULI, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex, France) Ms Morgane Lendrin (Université de Bordeaux, CNRS, CEA, CELIA (Centre Lasers Intenses et Applications), UMR 5107, Talence, France) Mr Pierre Guillon (LULI, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex, France) Zofia Rusiniak (Institute of Plasma Physics and Laser Microfusion)

Presentation materials