Ponderomotive Force Induced Dual-layer Structure of Particlespout
Yen-ren Chen1*, Hsien-wen Chao2, Shih-chieh Fong2, Shih-chin Chang3, Tsung-shune Chin4, Tsun-hsu Chang2
1Institute of Material Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan
2Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
3Department of Material Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan
4Department of Material Science and Engineering, Feng Chia University, Taichung, Taiwan
* presenting author:陳彥任, email:yrchen1988@gmail.com
A new phenomenon has been observed as tornado-like particlespout with dual- layer structure in a specially designed microwave cavity. Ionic crystals, such as sodium chloride and potassium chloride, were heated by microwave under a specific resonant mode. Beyond the melting point, the particles began to evaporate and move upward due to thermal convection. These particles formed a funnel shape with obvious two layers, compared with the ones by conventional heating formed only a single but unstable columnar vortex. The dual-layer structure performed different radii with the two ionic crystals under the same temperature, even the average particle sizes did, too. A theoretical model is proposed which attributes the observed phenomenon to the rotational kinematics together with the ponderomotive force. These two effects confine the particles to the inner and outer bounds, respectively.


Keywords: Ponderomotive force, microwave, ionic crystal