Ion energy and angular distributions onto polymer surfaces delivered by dielectric barrier discharge filaments in air: I. Flat surfaces

Abstract

In atmospheric pressure discharges, ion energies are typically thought to be thermal with values dominantly <1 eV. In the heads of filaments in dielectric barrier discharges (DBDs), electric fields can exceed 200 kV cm −1 when the filament is far from a surface. As the filament approaches and intersects a dielectric surface, much of the applied potential is compressed into the voltage drop across the head of the filament due to the high conductivity of the trailing plasma channel. When the filament strikes the surface, this voltage is transferred to the resulting sheath and into the material of the surface. The degree of electric field compression depends on the dielectric constant ε/ε 0 of the surface. Upon intersection of the filament with the surface, the electric fields in the resulting sheath can exceed 400-800 kV cm −1 , with larger values corresponding to larger ε/ε 0. When accelerated in these fields, ions can gain energies across their mean free path (0.5-1 µm) up to 20 eV for dielectrics with low ε/ε 0 and up to 150 eV for dielectrics with high ε/ε 0 , albeit only for the duration of the intersection of the streamer with the surface of a few ns. In this paper we report on results from a computational investigation of the ion energy and angular distributions (IEADs) incident on dielectric flat surfaces resulting from the intersection of DBD filaments sustained in atmospheric pressure air. We describe the transient and spatially dependent IEADs as the filament spreads across the polymer.

Mode Transition of Filaments in Packed-Bed Dielectric Barrier Discharges

“…Plasma catalysis can be realized by introducing dielectric packing beads (coated with catalyst material) in the discharge gap, forming a packed bed dielectric barrier discharge (PB-DBD) reactor. The DBD generally occurs in a filamentary mode by applying a high driving voltage [10][11][12][13][14], which induces a very fast ionization avalanche, propagating from powered electrode to grounded electrode, i.e., a so-called streamer [12,13,[15][16][17][18][19]. Each streamer starts when the driving voltage passes a certain threshold, and will further polarize the dielectric surface [20].…”

Numerical Modelling of Mutual Effect among Nearby Needles in a Multi-Needle Configuration of an Atmospheric Air Dielectric Barrier Discharge

“…Considering the complexity of the plasma processes created by DBDs, mathematical modelling and numerical simulations are essential tools used to increase our fundamental understanding of the subject [23][24][25][26][27]. Research on local discharge characteristics mainly focuses on the space-time evolution of particles (e.g., excitation and ionization by an electron of a neutral particle, recombination of electrons and ions, and electron thermal and non-thermal attachment and detachment processes), electron mean energy profile, and photo-ionization [28].…”

“…This research cannot be easily realized through experimental observation but must be conducted via theoretical analysis. With the advent of more powerful computers and more sophisticated algorithms, numerical modelling has been increasingly employed and will continue to benefit the investigation of non-equilibrium plasma caused by gas discharge [23][24][25][26]28,29].…”

Dielectric Barrier Discharge Characteristics of Multineedle-to-Cylinder Configuration

“…To investigate the DBD plasmas and the use of DBD plasmas in technological devices, three basic models are usually employed: fluid-hydrodynamic model, particle-in-cell/Monte Carlo collision (PIC/MCC) model and hybrid models [5,[15][16][17][18][19][20][21][22]. Fluid models have been developed both for low and high pressure discharges.…”

“…Fluid models have been developed both for low and high pressure discharges. Natalia et al reported a multi-fluid hydrodynamics simulation to investigate the ion energy and angular distributions incident on dielectric flat surfaces resulting from the intersection of DBD filaments sustained in atmospheric pressure air [16]. PIC/MCC method provides the most detailed information on the properties (e.g., velocity distributions) of the electrons, ions and atoms [19,20].…”