Excitation and Stabilization of Collisional Drift Instability by Electron Density Modulation. I

In an ECRH plasma, the electron density can be modulated by modulating the microwave power to produce the plasma. It is shown that a collisional drift wave is excited by modulating the electron density of the plasma in a marginally unstable region. When the spontaneous excitation of the instability arises, its dynamic and feedback stabilizations are carried out by the density modulation whose frequency is around that of the instability. As the instability is stabilized, the ion loss flux across the magnetic field is observed to decrease.