A two-dimensional electrostatic model describing unitedly the phenomena of the transitlo-nal and intermediate regions in ESF is derived from the plasma two-fluid equations taking the ion-neutral collisional effect into account.

• 本文从计入离子-中性粒子碰撞频率Vin效应的等离子体二流体方程组出发；导出统一描述ESF小尺度和中小尺度区域现象的二维静电模型.