The Aldean repulsor beam pushing the Enterprise away from the planet

A repulsor beam was a type of energy beam or weapon that used force to move an object rather than energy to destroy it.

Wesley Crusher, under the influence of polywater intoxication, once constructed a small repulsor beam from his model tractor beam in 2364 by modifying its circuits and connecting it to ship power. Later he applied the same modifications to the tractor beam of the USS Enterprise-D to push the ship away from an approaching stellar core fragment. (TNG: "The Naked Now")

The planetary defense system of Aldea included a powerful repulsor beam that could be used to push possible aggressors away. In 2364, the Aldean beam was used on the Enterprise-D, resulting in the vessel being pushed several light years away in an instant, far enough that at maximum warp it took them three days to reach the planet again. The Aldeans boasted that this was only a small demonstration, and that they could have just as easily pushed the Enterprise-D so far away that by the time they returned, their kidnapped children would be grandparents. Picard noted in his log that a weapon of this magnitude could have also easily been used to disintegrate the ship. (TNG: "When The Bough Breaks")

A similar technology was encountered in "That Which Survives", set in 2269, when the USS Enterprise was pushed almost a thousand light years by the Kalandans Outpost. Montgomery Scott proclaimed this to be impossible.
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