# Research

### High order fluid modeling of streamer discharges

Streamer discharges pose basic problems in plasma physics, as they are very transient, far from equilibrium and have high ionization density gradients; they appear in diverse areas of science and technology. The present research focuses on the derivation
and numerical implementation of a high order fluid model for streamers. Using momentum transfer theory, the fluid equations are obtained as velocity moments of the Boltzmann equation; they are closed in the local mean energy approximation and coupled
to the Poisson equation for the space charge generated electric field. The high order tensor in the energy flux equation is approximated by the product of two lower order moments to close the system. The average collision frequencies for momentum and
energy transfer in elastic and inelastic collisions for electrons in molecular nitrogen are calculated from a multi term Boltzmann equation solution. Among many important issues, the following are particularly investigated :

• correct implementation of transport data in streamer models

• accuracy of the two term approximation for solving Boltzmann’s equation in the context of streamer studies

• evaluation of the mean-energy-dependent collision rates for electrons required as an input in the high order fluid model

• inaccuracies of simulation results caused by an inconsistent implementation of transport data into our high order fluid model

• comparison with the first, second and MC-PIC models.

This is joint work Assoc. Prof. Dr. Sasa Dujko, Assoc. Prof. Dr. R. White and Prof. Dr. U. Ebert.

### Publications

2. *High-order fluid model for streamer discharges: II. Numerical solution and investigation of planar fronts*, **A.H. Markosyan**, S. Dujko, U. Ebert; *J. Phys. D: Appl. Phys.* **46** 475203
(2013), doi: 10.1088/0022-3727/46/47/475203 [pdf].

1. *High-order fluid model for streamer discharges: I. Derivation of model and transport data*, S. Dujko, **A.H. Markosyan**, R.D. White, U. Ebert; *J. Phys. D: Appl. Phys.* **46** 475202 (2013),
doi: 10.1088/0022-3727/46/47/475202 [pdf].

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