A fluid model has been used in this work to analyze the electric and
energetic behavior of a low-pressure DC glow discharge in Ar chosen as a gas
test. The governing equations are the first three moments of the Boltzmann
transport equations under their complete form without using the
classical-drift-diffusion approximation for the momentum transfer equation
while the energy conservation equation involves both thermal and drift
energies. In the framework of the local energy approximation, the basic data
needed more particularly in the collision source terms for both momentum
transfer and energy equations are determined from a multi term solution of
Boltzmann equation. Due to the strong coupling with electric field obtained
from Poisson equation and the high sheath gradients, the transport equations
are numerically solved using a powerful Galerkin finite elements method.
This model, after a validation from comparison with literature results, is
then used to analyze the convective and drift energy effects on the electric
discharge characteristics. Present results show a large influence of the
convective term in comparison to the drift-diffusion approximation, mainly
on the electric field and charged density profiles due to the antagonist
effect induced by this term on the electron and ion motion which reinforces
the charge space. Present results show also the discharge characteristic
changes mainly in the sheath due to the drift energy consideration.