Development of a portable expansion cloud chamber for high-energy laser experiments

A portable expansion cloud chamber is under development to investigate the interaction of high-energy lasers (≥3 kW) with cloud and fog structures under controlled, reproducible conditions. This facility is designed to support research in security and defense applications. The main goal is to analyze laser propagation, target acquisition, and beam attenuation in complex atmospheric environments. The system features a dual-mode adiabatic expansion mechanism, enabling both gradual evacuation via pumps and rapid pressure drops using a secondary pressure tank, allowing precise control over cloud and fog formation through decompression. The main chamber, a double-walled vacuum cylinder with an internal diameter of 2m and a length of 10m, is housed within a 45-foot container frame. This design ensures precise regulation of environmental conditions, covering a broad operational range: temperatures from −50 °C to +40 °C, relative humidity from 0% to 100%, and pressure from 100 to 1100mbar. Uniform air distribution is achieved using different fans, while an array of heat plates can generate turbulent states. A comprehensive set of sensors provides real-time monitoring of all relevant environmental parameters at different points within the chamber. The number of sensors is deliberately to ensure redundancy and robustness. The primary application of the chamber is testing the effectiveness of high-energy laser systems in adverse weather conditions. Additionally, the system can be used to study the impact of aerosols, clouds, and fog on laser transmission and to optimize countermeasure strategies. Beyond military applications, the chamber also supports fundamental research in atmospheric optics, remote sensing, and climate science.