Deduction of plasma ow in a collisional un-magnetized plasma

An argon plasma generated by a torch arc discharge with pressure of 50 torr and power of 800 watts is characterized by a single and Mach probes. A uid model for the owing un-magnetized plasma with the generic two-dimensional feature is established by taking moment of one-dimensional Boltzmann transport equation with contribution of ionization and ion-neutral collisions. Using a new relation between Mach number (M0 ≡ vd/ √ (Te + Ti)/mi, Te=electron temperature, Ti=ion temperature, mi= ion mass, and vd=drift velocity) and ratio (R) of the upstream to downstream ion sheath current densities, the plasma ow at the center of the torch plasma is deduced about 1 km/sec, which is 5 ∼ 6 times smaller than those by the previous collisionless models and is more close to those by other experimental and numerical results for the similar cases.