Observations of ball-lightning-like plasmoids ejected from silicon by localized microwaves

Yehuda Meir, Eli Jerby*, Zahava Barkay, Dana Ashkenazi, James Brian Mitchell, Theyencheri Narayanan, Noam Eliaz, Jean Luc LeGarrec, Michael Sztucki, Oleg Meshcheryakov

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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 clusteringand 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.

Original languageEnglish
Pages (from-to)4011-4030
Number of pages20
Issue number9
StatePublished - 2013


  • Atmospheric plasma
  • Ball lightning
  • Complex plasma
  • Dusty plasma
  • Localized microwaves
  • Microwave heating
  • Nanoparticles
  • Plasmoids
  • Silicon spheres


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