Electronegativity effects on plasma dynamics in He/O$_2$ RF microplasma jets at atmospheric pressure

TL;DR

This study explores how electronegativity influences plasma behavior in He/O$_2$ RF microplasma jets at atmospheric pressure, combining experimental spectroscopy with hybrid simulations to understand mode transitions.

Contribution

It introduces a hybrid modeling approach and provides detailed insights into electronegativity effects on plasma modes and electric field in microplasmas.

Findings

Electronegativity causes inhomogeneities in the electric field.

Good agreement between experimental and simulation results.

Electronegativity modulates electron excitation dynamics.

Abstract

This work investigates the transitions between ohmic mode and Penning-Gamma mode in a capacitively coupled radio frequency micro atmospheric pressure plasma jets (CCRF $\mu$APPJ) operated in He/O$_2$ mixtures by comparing phase-resolved optical emission spectroscopy (PROES) measurements of helium excitation with numerical simulations. The simulations employ a hybrid model that treats electrons kinetically via PIC/MCC, while ions and neutrals are modeled fluid dynamically. These results reveal that increasing electronegativity causes inhomogeneities in the bulk electric field, consequently modulating electron impact excitation dynamics. A good agreement was found between experiments and simulations.