Asea Brown Boveri Ltd. (ABB) Award - 2024 - Stanislav Sergeev

For his pioneering work combining plasma physics, acoustic engineering and active control. His “plasmacoustic metalayer” concept is a game-changer in soundproofing techniques, allowing for the first time sound wave manipulation without resorting to any tangible material.

Environmental noise has an immense impact on public health, making the development of noise reduction technologies crucial. Existing methods typically fail to be compact, broadband, lightweight, and mechanically robust. Passive absorbers are bulky and inefficient in low frequencies or narrowband. Active noise reduction methods, including active noise cancellation and acoustic impedance control, extend the bandwidth of operation and remain small compared to a wavelength. Electrodynamic loudspeakers are a conventional choice for controlled transducers but are limited by their fragile diaphragm, relatively high weight, and inherent resonant nature, restricting the bandwidth of control. This thesis focuses on developing a plasma-based electroacoustic transducer for active sound control applications. The acoustic field is manipulated by partially ionizing a thin air layer with an atmospheric corona discharge and controlling it with an alternating electrical field. Utilizing the unique physics of this transducer with the developed analytical model, perfect sound absorption and tunable acoustic reflection are achieved over two frequency decades, from several Hz to the kHz range. This unprecedented bandwidth and compactness, along with simplicity, lightweight, and flexible design, open new doors in noise control applications and acoustic metamaterials.