Feedback control of a class of plasma instabilities

We consider feedback control of an important class of plasma instabilities consisting of drift waves, flutes, and trapped particle modes. For all practical purposes these are shown to be completely observable and controllable with a single pair of a sensor and suppressor. We develop detailed stabilizing feedback controllers for a multimode collisional drift wave instability in a
Q
-machine and for a dissipative trapped electron mode in a linear machine.