https://phys.org/news/2018-05-versions-han-solo-blaster-theyre.html

The key to understanding Star Wars technology is plasmas – a so-called "fourth state of matter" (in addition to solids, liquids and gases). This comprises freely flowing electrically charged particles which naturally interact with electric and magnetic fields. Plasmas are common in space but they rarely exist naturally on Earth. However, it is possible to produce them in laboratories.

A common misconception about blasters is that they are laser weapons. But within the Star Wars canon, people realised that this wouldn't make sense. Instead writers stated that a blaster was "any type of ranged weapon that fired bolts of intense plasma energy, often mistaken as lasers" and that it "converted energy rich gas to a glowing particle beam that could melt through targets". This means that blaster bolts (glowing projectiles) are simply blobs of plasma – similar to a lightsaber flying through the air.