Researchers determine new method to measure high-energy-density plasmas and facilitate fusion by inertial confinement

Researchers determine new method to measure high-energy-density plasmas and facilitate fusion by inertial confinement

Nature Communications (2022). DOI: 10.1038/s41467-022-30472-8″ width=”800″ height=”437″/>

Experimental setting. Schematic of the experimental setup for each photo: (i) selection of a 500 keV energy proton beam from an initial TNSA broadband spectrum generated by the main beam, (ii) WDM sample generation by the heating beam, (iii) low speed measurement. proton energy spectrum of the selected beam after passing through the WDM target and (iv) characterization of the WDM sample by SOP and XPHG diagnostics. Typical raw experimental data obtained for each photo are shown for the magnet spectrometer as well as for SOP and XPHG diagnostics. Credit: Communication of nature (2022). DOI: 10.1038/s41467-022-30472-8

An international team of scientists has discovered a new method to promote the development of fusion energy through increased understanding of the properties of hot dense matter, an extreme state of matter similar to that found at the heart of giant planets such as Jupiter.

The findings, led by Sophia Malko of the US Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), detail a new technique for measuring the “stopping power” of nuclear particles in plasma using ultra-intense high-repetition-rate lasers. Understanding the stopping power of protons is particularly important for fusion in the inertial limit (ICF).

Powering the sun and stars

This process contrasts with fusion creation at PPPL, which heats plasma to temperatures of millions of degrees in magnetic containment facilities. Plasma, the hot, charged state of matter composed of free electrons and atomic nuclei, or ions, fuels the fusion reactions in both types of research, which aim to replicate on Earth the fusion that powers the sun and stars as a safe, clean source. and virtually unlimited energy to generate the world’s electricity.

The “stopping force” is a force acting on charged particles due to collisions with electrons in matter, which result in energy loss. “For example, if you don’t know the stopping power of protons, you can’t calculate the amount of energy deposited in the plasma and therefore design lasers with the right energy level to create fusion ignition,” said Malko, lead author of a papers emphasizing findings in Communication of nature. “Theoretical descriptions of the stopping power of high-energy-dense matter and especially hot dense matter are difficult and measurements are largely lacking,” she said. “Our work compares experimental data of proton energy loss in hot dense matter with theoretical models of the stopping power.”

The Communication of nature The research investigated the stopping power of protons in a largely unexplored regime, using low-energy ion beams and hot dense laser-produced plasmas. To produce low-energy ions, the researchers used a special magnet-based device that selects the low-energy fixed energy system from a broad spectrum of protons generated by the interaction of lasers and plasma. The selected beam then passes through hot dense matter driven by the laser and its energy loss is measured. Theoretical comparison with experimental data showed that the closest fit did not strongly agree with classical models.

Instead, the closest agreement came from recently developed first-principles simulations based on a many-body, or interacting, quantum mechanical approach, Malko said.

Precise stop measurements

Precise stop measurements can also advance understanding of how protons produce what is known as fast ignition, an advanced inertial fusion scheme. “In proton-driven fast ignition, where the protons must heat the compressed fuel from very low to high temperature states, the stopping power of the protons and the state of the material are tightly coupled,” Malko said.

“The stopping power depends on the density and temperature of the material state,” she explained, and both are in turn affected by the energy deposited by the proton beam. “Thus, uncertainties in the stopping power lead directly to uncertainties in the total energy of protons and laser energy required for ignition,” she said.

Malko and her team are conducting new experiments at the DOE LaserNetUS facilities at Colorado State University to extend their measurements into the so-called Bragg peak region, where maximum energy loss occurs and where theoretical predictions are most uncertain.

Co-authors of this paper included 27 researchers from the US, Spain, France, Germany, Canada and Italy.

Discovering a new way to bring the energy that powers the sun and stars to Earth

More information:
S. Malko et al., Slow Speed ​​Proton Stopping Measurements in Hot Dense Carbon, Communication of nature (2022). DOI: 10.1038/s41467-022-30472-8

Provided by Princeton Plasma Physics Laboratory

Citation: Researchers determine new method to measure high-energy-dense plasmas and facilitate fusion through inertial confinement (2022, September 19) Retrieved September 20, 2022, from method-high-energy-density-plasmas .html

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