Really? I wouldn't have thought fortify magika. I figure my Intelligence is going to be maxed by the end of the game so I'd have all the magika I'd need. But ok, if that's the case, what would you name it? With Fortify Strength, I was going to go with something like "Mighty Bonds". I can't think of anything for a magika enchantment that fits withe the prison theme.
Base magicka is Int * 2, so without enchantments, racial or birthsign bonuses, you'll end up with 200 magicka. Don't know if that's enough; frankly, I've never had a character reach "end game".
How about "Braces/Bonds of Aetherius"? Aetherius is said to be where magicka originates.