Disturbances in the interplanetary medium following solar flares occurring far from the heliospheric streamer but near the earth helioprojection

A study is made of the MHD structure of interplanetary disturbances that occur far from the streamer but near the earth helioprojection. It is found that flares in a 'weak' field (3-4 micro T) give rise to structures with magnetic clouds, whereas after flares in a 'strong' field (10-14 micro T), the clouds are either absent or are significantly changed, probably due to the screw instability. The disturbances produced by flares in a 'weak' field are characterized by a low velocity, and their travel toward the earth can be estimated from the head shock front and from the cloud boundary and axis.