New! Sign up for our free email newsletter.
Science News
from research organizations

Shedding (high-power laser) light on the plasma density limit

Japanese researchers show plasma density limit for the interaction of high-power lasers with matter

February 20, 2018
Osaka University
Researchers theoretically proposed the existence of density limit for hole boring by laser light on matter. They derived the maximum plasma density as a function of laser intensity, where hole boring stops and plasma blowout occurs. Theory and simulation of an ultra-high-pressure plasma state, wherein plasma's density pushes light back in the direction of the laser source, contribute to fundamental understanding, and provided grounding for applications such as laser-induced nuclear fusion.

The interaction of high-power laser light sources with matter has given rise to numerous applications including; fast ion acceleration; intense X-ray, gamma-ray, positron and neutron generation; and fast-ignition-based laser fusion. These applications require an understanding of energy absorption and momentum transfer from the high-intensity lasers to plasma particles.

A group of Japanese researchers led by Osaka University has proposed that substances heated with high-power lasers produce an ultrahigh pressure plasma state, comparable with those found at the centers of stars, and that the surface tension of the plasma can push back light. Since lasers with energies capable of heating material sufficiently to create this pressure had not been available to date, the process had not been considered. Their work published in Nature Communications describes their theory and supporting simulations.

"Understanding extreme high pressure states created by laser light interacting with materials is crucial for laser-based applications," co-author Yasuhiko Sentoku says. "Our theory proposes that steepening of surface plasma by intense laser, i.e., hole boring, is stopped eventually by ultrahigh plasma pressure, and a new stage of plasma heating appears."

They derived the limit density for laser hole boring, which corresponds to the maximum plasma density laser light can reach. They found that after reaching the density limit, the surface plasma starts to blowout towards the laser, even if the laser irradiates the plasma continuously.

The researchers' theory explains the transition to blowout in terms of a balance relationship between the pressure of the laser light and that of the surface plasma. The theory provides a guideline in controlling electron energy which is important for applications such as ion acceleration and pair plasma creation.

"We also derived the time scale for the transition from hole boring to blowout, showing that our findings will be applicable for multi-picosecond laser experiments," lead author Natsumi Iwata says. "We hope our work will provide a grounding for application focused research, for example laser initiated nuclear fusion."

Story Source:

Materials provided by Osaka University. Note: Content may be edited for style and length.

Journal Reference:

  1. Natsumi Iwata, Sadaoki Kojima, Yasuhiko Sentoku, Masayasu Hata, Kunioki Mima. Plasma density limits for hole boring by intense laser pulses. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-018-02829-5

Cite This Page:

Osaka University. "Shedding (high-power laser) light on the plasma density limit." ScienceDaily. ScienceDaily, 20 February 2018. <>.
Osaka University. (2018, February 20). Shedding (high-power laser) light on the plasma density limit. ScienceDaily. Retrieved November 29, 2023 from
Osaka University. "Shedding (high-power laser) light on the plasma density limit." ScienceDaily. (accessed November 29, 2023).

Explore More
from ScienceDaily