Narrow Results

We predict the instability of plasma waves excited by a DC current in the field-effect transistors (FETs) with a partly gated channel. The excitation of plasma waves is due to amplified reflection from the boundary of the gated and ungated regions. The boundary also supports the turbulent edge modes whose increment strongly depends on the ratio of the carrier densities in the two FET regions.

We predict the instability of plasma waves excited by a DC current in the field-effect transistors (FETs) with a partly gated channel. The excitation of plasma waves is due to amplified reflection from the boundary of the gated and ungated regions. The boundary also supports the turbulent edge modes whose increment strongly depends on the ratio of the carrier densities in the two FET regions.

In a cylindrical cold rf plasma, a variety of drifts and other sorts of waves are usually observed; when a turbulence is created, the state becomes chaotic and then the plasma turns out to be more unstable. In the present work, an external signal is enforced on the plasma's waves (or turbulence), which strongly affects the physical magnitudes of the plasma instabilities. The final result is that plasma stabilization occurs when plasma waves are synchronized with the external signal. Moreover, nonlinear phenomena occur, such as a vigorous coupling among the waves' frequencies, which affect the Hall conductivity. Another significant observation is the influence of boundaries on the interaction waves.

Beam-plasma instabilities represent a key issue for the physics of relativistic collisionless shocks. They play a role in the very shock formation when triggered by the collision of two plasma shells. Once the shock is formed, Fermi accelerated particles at the shock front interact with the upstream medium. In this phase, the beam-plasma instabilities can amplify the upstream magnetic field and generate small scale turbulence. Both kind of effects are believed to play a major role in the generation of High Energy Cosmic Rays and Gamma Ray Bursts.