256 / 2023-04-21 20:18:45

Effective suppression of bundling laser plasma instabilities using multi-beam-smoothing methods

laser plasma instabilities,bundle,beam smoothing,inertial confinement fusion

惯性约束聚变物理学 > 黑腔和激光等离子体相互作用-I

On hyper-scale laser facility, several beams will be bundled together and injected into the target chamber through a common port. This specific configuration could lead to laser plasma interaction (LPI) processes that are quite different from those in experiments on a normal-scale facility, as well as to more options for suppressing LPI via combination of different laser smoothing techniques on the beams in a bundle. For studying LPI of a bundle of beams in ignition-scale plasmas, a novel laser facility named Shenguang Octopus has been developed[1]. On this facility, eight laser beams are bundled together, operated at 351nm with a total energy of 30kJ, forming a 0.7-mm diameter focal spot with an overlapped intensity of up to 2.5×10¹⁵W/cm². A series of LPI experiments have been performed[1-3] by axially irradiating a gas-filled gold hohlraum target from one side. Several beam smoothing techniques, such as mixed polarizations, smoothing by spectral dispersion, and “multi-color” mode, are demonstrated to be effective in suppressing LPI under current conditions.