What is the difference?
The persona is what your protagonist projects, what image she cultivates and how she wants to be perceived. The character is what drives her inside; it’s what she lives with, or faces in the dark of the night.
An analogy might be this: the outside of a car is the protagonist’s persona. What’s inside – the engine – is the character. It’s the engine that moves a car forward.
Does your protagonist have a flashy sports care exterior, and a wimpy two cylinder engine? Is it a rough and patched car body, with a steady and reliable engine? Is it a shiny car, with strong, wild force inside? The permutations and combinations are endless.
So what’s inside your protagonist? What’s her true character like? Once you know that you’ll know what she’s likely to feel, think and do. You’ll know how her actions will move the story forward. But it’s also what’s inside – the character – that determines in part the kind of persona he/she feels the need to cultivate and project. Sometimes personas are cultivated to compensate for inner character vulnerabilities and weaknesses. So many possibilities...