When it is used,the jar intensifier is connected on the top of drill collar and on the lower end of drill stem.When the fishing tool engage the fish and the drill tool is lifted up,the silicone oil in the top chamber of piston is compressed and a large number of energy is thus stored.During lifting,when top jar reach up to free impact stroke,the stored energy in the jar intensifier will suddenly release,the energy suddenly released will provide a very large acceleration for drill collar and top jar to move upward.When the top jar reaches up to max.Stroke,a strong top jarring action will impact directly on the fish,as a result,large acceleration for drill collar and top jar to move upward.When the top jar reaches upto max.Stroke,a strong top jarring action will impact directly on the fish,as a result,one time jarring is produced,and more times jarring will be effected by repeating this course.