An approximate method is presented to take account of interaction of p
ositive streamers simultaneously propagating between a wire and a plat
e. The method is based on a quasi-2D positive streamer model modified
by inclusion in the expression for electric field of an additional ter
m describing the field of charges of all streamer channels in the gap.
All streamers are assumed to be identical and to move parallel to eac
h other to the plate from points equidistantly distributed along the w
ire surface. The model is used for calculation of streamer dynamics in
atmospheric air for conditions under which simultaneously propagating
streamers have been observed, it is shown that taking account of stre
amer interaction improves the agreement of the calculated dependence o
f streamer velocity on its length with the experimental one.