Executive Summary : | Strongly coupled plasma states, found in stars, the core of giant planets, and other astrophysical objects, are challenging to create and study in laboratory conditions. These states are created by high intense short pulsed excitations and require challenging time-resolved measurements for probing. The project aims to explore strongly coupled plasma states of carbon by directly observing their optical and structural properties. These extreme states of carbon have received little attention compared to other phases like graphite, diamond, and carbon vapour. Unresolved problems such as the metallic nature of strongly coupled carbon plasma or liquid-liquid phase transition (LLPT) in these extreme phases of carbon will be addressed. The project will employ femtosecond pump-probe diagnostics for time-resolved optical characterization of the transient phases of carbon. A thin graphite sample will be excited by an intense femtosecond laser pulse, and a time-delayed probe pulse reflection will be monitored to capture phase transition dynamics. The femtosecond probing will allow the measurement of the refractive index of strongly coupled carbon plasmas at various excitation levels, a step towards uncovering the debated metallic phases of highly-coupled carbon plasma. Further investigation will involve femtosecond time-resolved x-ray measurements on laboratory table-top scales to fully characterize the structure and establish the possibility of liquid-liquid phase transition. X-ray absorption spectroscopy (XAS) will be used as a probe. |