Experimental and numerical study of the dynamics of a μs helium plasma gun discharge with various amounts of N2 admixture
Résumé
These last years, atmospheric pressure plasma jets formed by pulsed helium discharges
ignited in thin dielectric tubes have been extensively studied due to their potential for
biomedical applications. So far, most experiments have been dedicated to the study of the
plasma plume. For endoscopic treatments, it is also important to better understand and
optimize the propagation of discharges in long dielectric tubes as catheters. First we present
an experimental and numerical study on the dynamics of a s helium plasma discharge
with N2 admixture in a long dielectric tube. We compare the velocity of the discharge
front for various amounts of N2 and dierent applied voltages and show a good agreement
between experiments and simulations. Second, we compare time-resolved measurements and
simulations of longitudinal and radial electric elds associated with plasma propagation in
the dielectric tube and in the plasma plume. It is interesting to note that measurements
obtained with a probe located outside the dielectric tube are in excellent agreement with
simulations. This allows to infer from simulations the time evolution of the electric eld on
the discharge axis which is a key parameter for applications.
Acknowledgment: The authors acknowledge the computational resources of the
Mesocentre of Ecole Centrale Paris.