OTSI of lower-hybrid waves in large- and small-size devices

Oscillating two-stream instability (OTSI) of lower-hybrid pump waves has been studied in both large- and small-size devices. For large-size devices, the instability has been investigated by considering fast-ion-mode side-bands and employing local theory. The convective threshold due to the finite extent of the pump has been calculated. For small-size devices, the instability has been investigated by ignoring thermal effects on the side-bands but employing nonlocal theory. We have found that there is no important change in growth rates in both cases.