3.10 Feedback Stabilization and Measurement of Instability Coefficients in Electron‐Hole Plasmas

More than 25db suppression of an $m=0$ (sausage) standing wave is obtained by feeding back only 0.5% of the instability oscillation output power. This mode is spontaneously generated at injected plasma currents of as little as∼1A (corresponding to a plasma density of ∼10¹⁴ cm⁻³) in p‐InSb with an applied axial magnetic field of ∼400G. The linear growth rate is measured to be $γ=8×106 sec−1$⁠. The first and second nonlinear saturation coefficients are determined to be $α=3×1010 sec−1$ and $β=0$⁠. As either the current or magnetic field strength is increased, $γ$ and $α$ increase.