I assume a travel nurse is kind of like the agency locums in ireland and the uk?
Dont have experience to confirm;
A travelling nurse, is a nurse that specializes in meeting short term staffing crunches, or in rotation queues with essential but remote areas of operation where attracting skilled full time staff is not possible, but where staff is vitally necessary.
Consider a rural hospital, out on some pacific island, that is a part of the public healthcare system. That hospital is the only hospital on the island, and services that island, and likely any surrounding islands. Patients would die in transport if ghey were attempted to be taken anywhere else, so the hospital *must* function. The island lacks the educational infrastructure needed to produce local staff nurses.
Where do the nurses needed to run the hospital come from?
Travel nurses!
(This happens in some remote parts of the country, like Alaska, where the hospitals are private, but owned by a large hospital network, and sustaining the hospital is a legal requirement for some other cherry arrangement in a more profitable locality, and thus similarly, *must function*, despite availability of local staffing.
Travel nurses also fill emergency staffing needs, such as "major earthquake destroys half of los angeles!" Or "hurricane levels entire state of georgia!", where a logistically unfeasible number of workers is needed, needed right now, and no, it cant wait.
Sadly, they are also often used as "instant scabs" during hospital pay/treatment disputes with local staff.