A quantum field forms in front of Voyager as it attempts to enter a quantum slipstream
A quantum field is an energy form which can be naturally found in a dark matter nebula. When artificially-produced, a quantum field can be used to generate a quantum slipstream.
In 2153, while observing a dark matter nebula, T'Pol attempted to monitor its quantum field as the nebula was being illuminated with metreon particles. Captain Archer told her to let the sensors do it, so that she could take the time to appreciate the spectacle of the nebula. (ENT: "First Flight")
In 2257, when Spock attempted to mind meld with the Red Angel, he found the being surrounded by a quantum field: an impermeable layer of energy. Through it, he was only able to perceive that the Angel was Human. (DIS: "If Memory Serves")
The quantum slipstream drive operated by routing energy through the main deflector, which then focused a quantum field, allowing the vessel to penetrate the quantum barrier. In 2375, the crew of the USS Voyager attempted to utilize quantum slipstream to return to the Alpha Quadrant, but constant phase variances in the quantum field ultimately made such a journey impossible. (VOY: "Hope and Fear", "Timeless")