Purusha is more narrowly focused on the distinction between the observer and the observed, while Atman is more broadly focused on the identity between the individual self and ultimate reality. However, both concepts ultimately point towards the same realization of liberation and recognizing the ultimate truth.
The individual soul and Supersoul are compared to two birds which reside in the same tree. One of them (jiva-atma) is eating the fruits of the tree, while the other (param-atma) is just witnessing the activities of his friend. The witness is the Lord, and the fruit-eater is the living entity. The fruit-eater (living entity) which is overcome by
1 Chaitanya means consciousness, while soul is an english word which could mean anything depending on the context. Sometimes soul is used to refer to subtle body. Sometimes soul denotes the jiva. Sometimes Soul refers to the Highest Brahman.
Jainism believes that souls (atmas) are distinguishable by their form as well as size and possess materiality. Some souls are extremely minute and may live in clusters while some, which reside in large animals such as elephants are much larger.
The short answer to your question is - There is not much difference between Soul (Atman) and Kundalini. They are just the different names or perspectives of the same principal. To be more specific, Kundalini is a major part, but not complete, of awareness or the Atman (Sanskrit) that we call as Soul (English).
.