What type of solar activity can give off bright and extensive auroras?

While solar flares do release a significant amount of energy and can cause auroras, the phenomenon most closely associated with the production of bright and extensive auroras is coronal mass ejections. When coronal mass ejections occur, they release large quantities of plasma and magnetic fields from the sun's corona into space. When these charged particles interact with the Earth's magnetosphere, they can create beautiful and expansive auroras, notably known as the Northern and Southern Lights.

Solar flares primarily involve bursts of radiation and do not typically contribute to the extensive display of auroras in the same way that coronal mass ejections do. Solar winds—streams of charged particles emitted by the sun—can also lead to auroras but are generally less intense than the effects produced by coronal mass ejections. Sunspots are regions on the sun associated with magnetic activity but do not directly cause auroras themselves; they are more related to the sun's overall activity and cycles.

Thus, coronal mass ejections are specifically linked to the creation of the bright and extensive auroras observed on Earth.