Agglomeration processes sustained by dust density waves in plasma: From injection to the formation of an organized structure

Simon Dap (1) , Robert Hugon (1) , David Lacroix (2) , Ludovic de Poucques (1) , Jean-Luc Briancon (1) , Jamal Bougdira (1)

1 IJL - Institut Jean Lamour
2 LET - Laboratoire d'études thermiques

In this paper, an experimental investigation of dust particle agglomeration in a capacitively coupled RF discharge is reported. Carbonaceous particles are produced in an argon plasma using acetylene. As soon as the particle density becomes sufficient, dust density waves (DDWs) are spontaneously excited within the cathode sheath. Recently, it was proven that DDWs can significantly enhance the agglomeration rate between particles by transferring them a significant kinetic energy. Thus, it helps them to overcome Coulomb repulsion. The influence of this mechanism is studied from acetylene injection to the formation of very large agglomerates forming an organized structure after a few dozens of seconds. For this purpose, three diagnostic tools are used: extinction measurements to probe nanometer-sized particles, fast imaging for large agglomerates and a dust extraction technique developed for ex-situ analysis.

Domaines: Plasmas

Simon Dap, Robert Hugon, David Lacroix, Ludovic de Poucques, Jean-Luc Briancon, et al.. Agglomeration processes sustained by dust density waves in plasma: From injection to the formation of an organized structure. Physics of Plasmas, 2013, 20. ⟨hal-02314404⟩