Observations of Ball-Lightning-Like Plasmoids Ejected from Silicon by Localized Microwaves

Materials

Yehuda Meir⁴  Eli Jerby¹  Zahava Barkay²  Dana Ashkenazi⁴  James Brian Mitchell⁵  Theyencheri Narayanan³  Noam Eliaz⁴  Jean-Luc LeGarrec⁵  Michael Sztucki³ 

[1] Wolfson Applied Materials Research Center, Tel Aviv University, Ramat Aviv 69978, Israel; E-Mail:;European Synchrotron Radiation Facility, Grenoble, F-38043, France; E-Mails:;Faculty of Engineering, Tel Aviv University, Ramat Aviv 69978, Israel; E-Mails:;Institut de Physique de Rennes, UMR N 6251 du CNRS, Université de Rennes I, 35042, Rennes cedex, France; E-Mails:

关键词: ball lightning;    plasmoids;    microwave heating;    localized microwaves;    dusty plasma;    complex plasma;    atmospheric plasma;    silicon spheres;    nanoparticles;   

DOI  :  10.3390/ma6094011

来源: mdpi

【 摘 要 】

This paper presents experimental characterization of plasmoids (fireballs) obtained by directing localized microwave power (<1 kW at 2.45 GHz) onto a silicon-based substrate in a microwave cavity. The plasmoid emerges up from the hotspot created in the solid substrate into the air within the microwave cavity. The experimental diagnostics employed for the fireball characterization in this study include measurements of microwave scattering, optical spectroscopy, small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Various characteristics of these plasmoids as dusty plasma are drawn by a theoretical analysis of the experimental observations. Aggregations of dust particles within the plasmoid are detected at nanometer and micrometer scales by both in-situ SAXS and ex-situ SEM measurements. The resemblance of these plasmoids to the natural ball-lightning (BL) phenomenon is discussed with regard to silicon nano-particle clustering and formation of slowly-oxidized silicon micro-spheres within the BL. Potential applications and practical derivatives of this study (e.g., direct conversion of solids to powders, material identification by breakdown spectroscopy (MIBS), thermite ignition, and combustion) are discussed.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.