- Nagai Group
Low Density Porous Materials for Laser Plasma Generation
Recent high power laser technology opens new aspect of laser acceleration and compact quantum beam sources with controlled targets. Low-density porous materials are promising for high efficiency target for laser energy conversion to quantum beam and high energy density states. The low-density porous meterials fabirication includes wide range of material chemistry however, it has not been focused. A new review paper published in Physics of Plasmas summarizes the efforts in recent years to fabricate targets out of low-density porous materials, and highlight that chemisty has its place in laser plasma experiments.
There is a wide range of requirements on the elemental composition of low density materials for laser targets depending on the output plasmas, i.e. temperature, density. Porous materials containing high atomic number (High Z) elements are required typically for high temperature heating of plasma. On the other hand, organic polymers are commonly used for both high density compression and heating.
Lower limit of the target density is around 1 mg/cm3. One of the major constraints of producing such low-density materials for laser targets is the target size (<1 mm). This is due to high power laser focused spot size limitation, which are generally smaller than 1 mm, while almost all commercial porous materials have a large aspect ratio of void per frame materials. In the region of the lowest density of porous materials, is comparable to the cut-off density of plasma (ncr) which allows the penetration and interaction of laser light with the frequency. This region is important because it allows penetration of laser through the target and gives a so-called volume heating of the target, which gives almost uniform density as target density before expansion.
Nanostructure effect is a new trend to control the character of the plasma via laser absorption and following process of transportation of energy.
If you are interested in such low density materials and laser plasma generation, please find the following open access papers.
1. "A Review of Low Density Porous Materials Used in Laser Plasma Experiments," by Keiji Nagai, Christopher S. Musgrave, and Wigen Nazarov, Physics of Plasmas 25 (3), 030501 (2018). The article can be accessed at http://doi.org/10.1063/1.5009689
and is introduced at Scilights Article https://aip.scitation.org/doi/10.1063/1.5029230
2. "High space resolution imaging plate analysis of extreme ultraviolet light (EUV) from Tin laser-produced plasmas"
Christopher S. A. Musgrave, Takehiro Murakami, Teruyuki Ugomori, Kensuke Yoshida, Shinsuke Fujioka, Hiroaki Nishimura, Hironori Atarashi, Tomokazu Iyoda, Keiji Nagai
Review of Scientific Instruments, 88 (3), 033506, (2017). (open access)
3. "Targets for high repetition rate laser facilities: needs, challenges and perspectives"
I. Prencipe, K. Nagai, et al.
High Power Laser Sci. Eng., 5 (e7), (31 pages), (2017).
4. "Efficient energy absorption of intense ps-laser pulse into nanowire target"
H. Habara, S. Honda, M. Katayama, H. Sakagami, K. Nagai, and K. A. Tanaka
Phys. Plasmas, 2016, 23 (6), 063105