Streamer propagating along the Z-axis, depending on the delay time between the laser pulse and the high-voltage pulse will meet either 1) a highly-ionized region of plasma (no delay); 2) high-temperature, high-density neutral gas layer (immediately after plasma recombination but before gasdynamic expansion); or 3) a combination of a high- and low-density gas layers (blast waves). The analysis shows that depending on the delay time between a laser pulse and a streamer, the streamer demonstrate different behavior. At small delay times (phase 1) both positive and negative polarities will not be able to propagate through the conductive plasma layer. Both negative and positive streamers will be able to propagate through the hot nonconductive gas layer (phase 2). Finally, when the low-density layer will be formed (phase 3), a streamer of positive polarity will not overcome this rarified gas layer, while a streamer of negative polarity will propagate further and finally will close the discharge gap. Thus, the proposed geometry will form a sort of “gasdynamic diode” with an asymmetric conductivity of the initially symmetrical air gap.