system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter/General] What is magic made of?

In Harry Potter, as well as many other fantasy series, magic is shown as a sort of spark/beam of light that shoots out of the wand. But what is that light? Is it plasma? Is is something else entirely?
gpt
In most cases, the light we see is the result of the magical energy exciting the electrons of the atoms which make up the air (and thus making the air glow).  It's somewhat similar to an electrical arc, but there's more variety because the magic obeys different rules than normal physics.  

If you could see into the Octarine, it would be even brighter and more prevalent.  That's part of why more spells seemed to result in beams of light later in Harry's time at Hogwarts; as a wizard trains he becomes more adept at perceiving octarine light.  Most of them don't even notice the change, it happens gradually and isn't mentioned much in the Hogwarts curriculum (unlike Unseen University, where it gets some emphasis).