| Abstract: | Cold‐gas traps enable the trapping of cold as well as heavy gases and aerosols in strong stationary ultrasonic fields. The effect can be explained by standard acoustic principles and it can be used to adjust temperatures down to –100 °C in the pressure nodes of a stationary ultrasonic field. In this investigation the cold‐gas traps have been generated by using a very powerful acoustic levitator. The cold‐gas traps have been improved, e.g., to study the formation and growth of ice and snow flakes from primary ice aerosol as well as freezing and melting processes of single and contact‐less levitated water drops. High‐speed monitoring (VIS, IR) of the first‐stage freezing process of levitated water droplets is reported. |
