Any noise generated by the aurora would take a long, long time to travel all the way to Earth, and the air up by the aurora is much too thin to carry sound. Auroras occur because Earth's magnetic field interacts with the solar wind, a tenuous mix of charged particles blowing away from the sun. This wind from the sun sweeps by Earth in the interplanetary magnetic field which is produced by the sun. We are protected from the solar wind's direct effects by Earth's comet-shaped magnetosphere, where the Earth's magnetic field is distorted by the interplanetary magnetic field and the solar wind. The electrical energy generated by the charged particles blowing across the Earth's magnetic field send charged particles down into the Earth's upper atmosphere.
Auroral light is similar to light from color television.
Auroral light is the from the air glowing as charged particles, particularly electrons, rain down along the Earth's magnetic field lines. The color of the aurora depends on the type of atom or molecule struck by the charged particles. Oxygen at lower altitudes, about 60 miles up, produces a brilliant yellow-green, the brightest and most common auroral color. The nitrogens create the purplish-red lower borders and ripple edges of the aurora. Auroral displays vary from night to night and during a single night.