Magic isn't common, though it isn't particularly rare. This form of magic is based very much upon the emotional state of the user, where essentially the potency and type of the magic is dependent on the kind and strength of the emotion being felt. (If you are interested in the finer details of the system, they can be found in this question.)
In this world, a particular kingdom has created a culture with a heavy stigma against those who can use magic. They are almost universally hated by the population, and the government takes steps to capture and control them. (The populous would help any efforts because of this general hatred.)
My question centers around this: how would they control them?
Ideally, there would be little to no chance of rebellion. A couple of thoughts came to my mind:
- A drug that serves two purposes, one being to induce a specific emotional state to facilitate more consistent and powerful magic, and the other to be extremely addictive so that they have to rely on the government to get their fix. This drug will make an appearance either way, but I'm not sure whether it will be a sufficient control on its own.
- Capturing their families and holding them hostage. This seems to me to be a heck of a lot of work, and the amount of magic-users would make the amount of people they have to keep quite cumbersome.
To sum up, what is the best way for a government to keep control of a fairly large number of magic-users without resorting to capturing those important to them?