Investigation on the origin of hot electrons in laser plasma interaction at shock ignition intensities

Abstract

Shock Ignition is a two-step scheme to reach Inertial Confinement Fusion, where the precompressed fuel capsule is ignited by a strong shock driven by a laser pulse at an intensity in the order of 10 16 W/cm 2 . In this report we describe the results of an experiment carried out at PALS laser facility designed to investigate the origin of hot electrons in laser-plasma interaction at intensities and plasma temperatures expected for Shock Ignition. A detailed time- and spectrally-resolved characterization of Stimulated Raman Scattering and Two Plasmon Decay instabilities, as well as of the generated hot electrons, suggest that Stimulated Raman Scattering is the dominant source of hot electrons via the damping of daughter plasma waves. The temperature dependence of laser plasma instabilities was also investigated, enabled by the use of different ablator materials, suggesting that Two Plasmon Decay is damped at earlier times for higher plasma temperatures, accompanied by an earlier ignition of SRS. The identification of the predominant hot electron source and the effect of plasma temperature on laser plasma interaction, here investigated, are extremely useful for developing the mitigation strategies for reducing the impact of hot electrons on the fuel ignition.

Metadata

Item Type:

Article

Authors/Creators:

Cristoforetti, G.
Baffigi, F.
Batani, D.
Dudzak, R.
Fedosejevs, R.
Filippov, E. D.
Gajdos, P.
Juha, L.
Khan, M.
Koester, P.
Krus, M.
Mancelli, D.
Martynenko, A. S.
Nicolai, Ph
Pikuz, S. A.
Renner, O.
Tentori, A.
Volpe, L.
Woolsey, N. https://orcid.org/0000-0002-2444-9027
Zeraouli, G.
Gizzi, L. A.

Funding Information: We would like to thank S. Hueller and J. Myatt for the useful discussion and the valuable suggestions. We would like to acknowledge financial support from the LASERLAB-EUROPE Access to Research Infrastructure activity within the EC’s seventh Framework Program (Application No. 18110033). This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200-EUROfusion). Views and opinions expressed are however those of the authors only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them. The involved teams have operated within the framework of the Enabling Research Project: ENR-IFE.01.CEA “Advancing shock ignition for direct-drive inertial fusion”. We also acknowledge financial support from the CNR funded Italian research Network ELI-Italy (D.M. No.631 08.08.2016). Staff members of the PALS Research Center appreciate a financial support (grant no. LM2023068) from the Czech Ministry of Education, Youth and Sports making possible to operate and utilize the PALS facility for interaction experiments reported in this article. The work of the JIHT RAS team was done in the frame of the State Assignment (topic No. 075-01129-23-00). This work was also supported by EPSRC grants EP/P026796/1 and EP/L01663X/1. Funding Information: We would like to thank S. Hueller and J. Myatt for the useful discussion and the valuable suggestions. We would like to acknowledge financial support from the LASERLAB-EUROPE Access to Research Infrastructure activity within the EC’s seventh Framework Program (Application No. 18110033). This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200-EUROfusion). Views and opinions expressed are however those of the authors only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them. The involved teams have operated within the framework of the Enabling Research Project: ENR-IFE.01.CEA “Advancing shock ignition for direct-drive inertial fusion”. We also acknowledge financial support from the CNR funded Italian research Network ELI-Italy (D.M. No.631 08.08.2016). Staff members of the PALS Research Center appreciate a financial support (grant no. LM2023068) from the Czech Ministry of Education, Youth and Sports making possible to operate and utilize the PALS facility for interaction experiments reported in this article. The work of the JIHT RAS team was done in the frame of the State Assignment (topic No. 075-01129-23-00). This work was also supported by EPSRC grants EP/P026796/1 and EP/L01663X/1. Publisher Copyright: © 2023, The Author(s).

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