In this paper, the modeling of linear plasma propulsion (LPP) using the snowplow model is presented to investigate the effect of anode length variation and atomic number of gases on plasma dynamics. The model employs four phases—axial, radial angular, reflected, and expansion—to describe both the dynamics and the propelled plasma in the LPP device. When the plasma in the LPP device is compressed and pinched, it is pushed through the extension tube that is attached to the discharge chamber. The anode length of the LPP device was varied in 2-cm increments, starting from 2 cm up to 18 cm, during the modeling process. To validate the agreement between the simulated and the experimental results, a comparison was performed using the discharge current signals. The results, as recorded in the paper, show that the propelled plasma length is not affected by variations in anode length or the atomic number of gases, while its velocity increases. However, the propelled plasma velocity decreases with the use of gases with higher atomic numbers, which also results in increased pinching time and phase time.