It's referred to as plasma in the primary literature: https://arxiv.org/abs/astro-ph/0608407 https://arxiv.org/abs/astro-ph/0608407 Many people use hot/ionised

It's referred to as plasma in the primary literature: https://arxiv.org/abs/astro-ph/0608407 https://arxiv.org/abs/astro-ph/0608407 Many people use hot/ionised gas and plasma interchangeably though. For example: https://academic.oup.com/mnras/article/389/2/967/974617 https://academic.oup.com/mnras/article/389/2/967/974617