COLLISIONLESS CURRENTS FOR CYLINDRIC PROBES IN A PLASMA WITH NON-MAXWELLIAN DISTRIBUTION OF THE ELECTRON-ENERGY

The radial model developed by ALLEN, BOYD, REYNOLDs and CHEN [1, 2] fo r the ion collection of Langmuir probes is extended to describe the ca se of a non-Maxwellian distribution of the electron energy. Assuming s tandard distributions, showing with respect to the Maxwell distributio n an increasing deficite of fast electrons as the parameter k of the d istribution increases, the electron-retarded current characteristic, t he potential distribution and the density profiles for electrons and i ons in the probe sheath, ion-current characteristics as well as graphs for the ion-density determination are calculated for different k. It is shown, that the application of the Chen model (k = 1) in plasma wit h k > 1 leads only to a small error in the ion-density measurement.