Research of Suppression Mechanisms for Laser–Plasma Instabilities
For laser fusion to become a viable long-term energy source, the direct-drive approach is essential. Among the two major challenges in direct-drive laser fusion—laser–plasma instabilities and nonuniform compression—our research focuses on suppression mechanisms for laser–plasma instabilities.
The direct-drive laser fusion process can be divided into four main stages. As the spherical fuel target is compressed by the drive laser, the dominant physical processes change with time and compression level.In the initial stage, laser ablation generates dense plasma, making laser–plasma interaction and plasma physics central research topics.
In the early compression stage, shock formation and the growth of surface perturbations, including Rayleigh–Taylor instability, play major roles. In the later compression stage, internal Rayleigh–Taylor instability can induce nonuniform compression, becoming a key control issue. In the final burning stage, fusion reactions occur in the extremely compressed fuel core.
This project explores a novel suppression mechanism for laser–plasma instabilities based on plasma photonics. Beyond reproducing established control methods, we seek to introduce an original and convergent concept that can rapidly advance our research to the forefront of the field. By exploiting the optical dispersion properties of plasma, we shape high-power laser pulses in phase, spectrum, and profile using plasma itself as an active optical medium. Leveraging our experience in Raman amplification, pulse compression, and plasma-wave physics, we aim to suppress SRS, SBS, and hydrodynamic instabilities through plasma-based phase control. This research is expected to mitigate density perturbations through temporal averaging, enhance laser energy coupling to the target, and provide a new paradigm for instability control in laser fusion.