Plasma Quantum Processes
Organized Session: Nov. 9th, 9:00am - 11:30am & 6:15pm – 6:45pm (JST)Scope and aim of the organized session:
Spectra of electromagnetic emission and absorption due to quantum interactions between
electrons, ions, atoms, and molecules in plasmas (excitation, ionization, recombination, dissociation,chemical reaction, etc.) provide vital clues to elucidate species and states of the plasma particles, theirtemperature and density, velocity fields, and electromagnetic fields in plasmas. Also, the microscopic
quantum interactions between the plasma constituents and the radiation and electromagnetic fields ofthe plasmas may result in development of macroscopic structures of the plasmas.
The Plasma Quantum Processes unit will be launched in NIFS to promote and accelerate joint
research in Japan and overseas on atomic and molecular processes in plasmas and development ofplasma spectroscopy, theory, simulation, and modeling with the aid of detailed atomic and molecularprocesses. The unit also aims to create new research fields through interdisciplinary collaborations on
atomic and molecular process research and database development. These will be performed by forminga research center network with universities and institutions.
This organized session aims to present academic plans for our unit, and to discuss prospects ofour future. The session consists of three parts. In the first part, our unit theme and academic plans will bepresented by Prof. Izumi Murakami (NIFS). Then, a main issue of our research subjects: development ofcollisional radiative model for non-LTE plasmas and atomic and molecular databases, will be discussed
in detail by Dr. Yuri Ralchenko (NIST, USA). In the last part devoted to discussions for prospects ofemerging collaborations, three relevant invited talks on highly charged ion physics and spectroscopy by
Prof. Nobuyuki Nakamura (ILS/UEC), high-power laser matter interaction by Prof. Yasuhiro Kuramitsu(Osaka Univ), and muon catalyzed fusion by Prof. Yasushi Kino (Tohoku Univ), will be presented.

Plans for invited talks:・ Dr. Yuri Ralchenko, National Institute of Standards and Technology (USA)(45+10min)
Although historically plasmas were primarily associated with classical physics, it was soon foundthat quantum processes play a crucial role in such important phenomena as, e.g., plasma radiation,
behavior of non-ideal plasmas, and interactions of electromagnetic fields with plasmas. I will
present an overview of the most advanced technique for determination of light emission fromdiverse plasmas, namely, the collisional-radiative modeling [1], that involves calculation of large
amounts of high-quality atomic data for various radiative, non-radiative, and collisional processes inplasmas. I will also describe the recent trends in development of atomic databases, in particular, thecritically evaluated databases for atomic structure and spectra [2].
[1] See, e.g., Modern Methods in Collisional-Radiative Modeling of Plasmas, edited by Yu.
Ralchenko (Springer, New York, 2016).
[2] URL https://www.nist.gov/pml/atomic-spectroscopy-databases.
・ Prof. Nobuyuki Nakamura, The University of Electro-Communications(25+5 min)An electron beam ion trap (EBIT), consisting of a Penning-like ion trap and a quasi-mono energetic
electron beam traveling through the trap, is a highly useful device for studying atomic processes ofhighly charged ions relevant to plasmas. At the University of Electro-Communications in Tokyo, wehave been using two complementary EBITs, a high-energy device called the Tokyo-EBIT, and acompact and low-energy device called CoBIT, for studying processes over a wide range ofparameters. In this talk, recent studies relevant to solar corona and fusion plasmas are presented
after a brief introduction of the devices.
[1] Priti et al., Phys. Rev. A 102 (2020) 042818. https://doi.org/10.1103/PhysRevA.102.042818[2] N. Nakamura et al., ApJ 921 (2021) 115. https://doi.org/10.3847/1538-4357/ac1c6f

・ Prof. Yasuhiro Kuramitsu, Osaka University(25+5 min)Recent development of ultra-intense laser technologies opened up a new regime of laser plasma
science such as relativistic electron and other quantum beam generations. However, it is still
difficult to generate relativistic ions; the highest proton energy has not reach 100 MeV yet. In thistalk our recent efforts on energetic ion acceleration using graphene will be presented. Graphene is asingle atomic layer thick, two-dimensional material made of hexagonal carbon lattice. We havedeveloped large-area suspended graphene (LSG) as a target of laser-driven ion acceleration, andhave conducted a series of experiments with LSG. We discuss unique features of graphene ionacceleration and a path to the relativistic ion acceleration.
[1] Y. Kuramitsu et al., Sci. Rep. 12 (2022) 2346. https://doi.org/10.1038/s41598-022-06055-4
・ Prof. Yasushi Kino, Tohoku University(25+5 min)A muon is an elementally particle simar to an electron, and can strongly squeeze the distance
between hydrogen nuclei forming a muonic molecule in which nuclear fusion reaction occurs
because of the 207 times heavier mass than an electron. The cyclic processes including thisintermolecular nuclear reaction is called the muon catalyzed fusion (µCF). We proposed anddemonstrated a new kinetics model of µCF [1] considering resonant muonic molecules by a newly
developed quantum few-body theory. The new kinetics model reproduces experimental
observations, showing higher cycle rates as the temperature increases, over a wide range of target
temperatures (T<800 K) and tritium concentrations. We are planning to experimentally confirm thenew model and to utilize it for new fusion reactor designs.
[1] T. Yamashita, Y. Kino, et al., Sci. Rep. 12 (2022) 6393.
https://doi.org/10.1038/s41598-022-09487-0

Figure 1. Tungsten spectra measured with Large Helical Device (LHD) and compact Electron BeamIon Trap (CoBIT) for extreme ultraviolet wavelength range.

Figure 2. Relativistic ion acceleration by irradiating large area suspended graphene with anultra-intense laser.

Figure 3. New kinetics model of µCF.