Direct measurement of the plasma response to electrostatic ion waves

Summary form only given, as follows. Plasma wave-wave and wave-particle interactions are studied in a linear magnetized plasma. The relatively quiet plasma (/spl delta/n/n/spl les/10%) is produced by an argon gas-discharge. The plasma density is n/sub e//spl sime/10/sup 9/ cm/sup -3/ and the electron/ion temperatures are T/sub e//spl sime/5 eV and T/sub i/=0.05 eV. A grid and a four ring antenna, both mounted on a scanning carriage, are used to launch electrostatic ion waves in the plasma. Laser induced fluorescence measurements of both the linear and the nonlinear plasma response to the wave fields are presented. The Vlasov-Poisson equations are used to explain the measured zero, first and second order terms of the ion distribution function in the presence of wave fields. In addition to the broadening (heating) of the ion distribution as we increase the wave amplitudes, induced plasma flows are observed both along and across the magnetic field.