A physical model for the recently advanced interpretation of the 3 kHz data [Gurnett, Kurth et al., 1993> is proposed. Basing on the results of the flow dynamical model of the heliosheath [Czechowski and Grzedzielski, 1993, 1994> we conclude that the post-shock solar wind (SW) plasma, cooled down by charge-exchange with neutral hydrogen of LISM origin, should form a high density layer on the inner side of the surface of the heliopause. The model allows us to estimate the plasma density profile and the size of the layer. These we use as input for MHD calculation of (1) a transient shock moving through this layer towards the heliopause and (2) of resulting 2&ohgr;p (frequency) drift of VLF emissions generated at the shock. For the heliopause distance L=150--180 A.U. our model reproduces both the time duration of the emissions and their typical frequency drifts. ¿ American Geophysical Union 1994