How does the tenant, or the landlord, force the roommate to move out. This is occurring in Alaska.

The roommate has to be violating terms of tenancy such as failing to pay rent, causing damage, making excessive noise.

How you proceed to evict depends on some questions about whether there is a lease, what it says, who is on it, how long the roommate has been there, whether the landlord/owner lives in the building and how many units there are. It would help to know which of the 3 you are.

Is the roommate on the lease?

You're in luck. You got an Alaska lawyer to answer your question. :)

If the roommate has no agreement with the landlord, it is in effect a subletting from the tenant to the roommate. The tenant would bring a forceable entry and detainer action (elsewhere known as eviction) against the roommate.

Whether the tenant needs to go to court or not depends on the circumstances. Did the roommate agree with the tenant to pay part of the rent?