Table-top experiment to simulate the strongly coupled plasma states of the Sun’s interior

Abstract

We built an experiment to produce high-density strongly coupled plasma (SCP) states in supercritical fluid (SCF) to emulate the Sun’s chromosphere and photosphere where the Coulomb coupling parameter () is of the order of unity. The SCF medium is chosen to minimize energy loss through phase transitions and particle transport [1]. Using ns laser pulse on argon SCF at 100 bar, SCPs are generated with electron density ~ 1e27 m^-3 and temperature ~ 1 eV, corresponding to  ~ 2 [2]. Combination with high voltage bias extends the lifetime of the SCP state from a few 100s ns to a few µs, opening an opportunity for precision measurements of thermodynamic transport parameters and equation of states. Pressure scan experiments suggest that the ionization potential reduction is the dominant ionization mechanism to attain the high density. Applications of SCPs to space explorations are discussed. *This work was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (Nos. 2019R1A2C3011474, 2022M3H4A1A04074153, and RS-2022- 00154676). [1] Seungtaek Lee et. al., Quasi-equilibrium phase coexistence in single component supercritical fluids, Nature Communications 12, 4630 (2021) [2] Seungtaek Lee, Juho Lee et. al., Characterization of strongly coupled plasmas produced in argon supercritical fluids, Plasma Physics and Controlled Fusion 64, 095010 (2022)