The role of electron-wall collisions in Hall thruster operation is studied through simulation of the electron energy distribution function (EEDF) inside the thruster channel. The electron Boltzmann equation is solved using the “local-field” approximation, using experimental results as input data. The equation takes into account inelastic losses due to ionizing collisions and wall-collisions, as...

The role of inelastic collisions in Hall thruster operation is studied through simulation of the electron energy distribution function (EEDF) inside the thruster channel. The electron Boltzmann equation is solved using the Lorentz approximation (two-term expansion) and the "local-field" approximation. The resultant zero-dimensional Boltzmann equation takes into account inelastic losses due to i...

A new approach leading to the development of gas analytical detectors is reported. The approach is based on measurements in the near-cathode plasma of fine structures associated with atomic and molecular plasma processes of the high energy portion of the electron energy distribution function (EEDF). A short (without positive column) dc discharge with cold cathode and conducting walls was used. ...

To investigate the electrical changes observed at plasma etching endpoints, experiments were performed in an inductively coupled, rf-biased reactor, during CF4/Ar plasma etches of silicon dioxide films on silicon substrates. The rf bias current, voltage, and impedance were measured vs. time during etching. Simultaneously, a Langmuir probe measured the electron and ion densities, ion current den...

The electron energy distribution function EEDF in a low-pressure inductively coupled plasma confined between two infinite plates separated by 10 cm is investigated using a one-dimensional particle-in-cell simulation including Monte Carlo collisions. At low pressure, where the electron mean free path is of the order of or greater than the system length, the EEDF is close to Maxwellian, except fo...

A model for electrons in partially ionized plasmas that self-consistently captures non-Maxwellian electron energy distribution function (EEDF) effects is presented. The based on the solution of scalar and vectorial velocity moments up to contracted fourth-order moment. set fluid (macroscopic) equations obtained with Grad's method exact expressions collision production terms are derived, conside...

Retarding field energy analyzers and Langmuir probes are routinely used to obtain ion electron distribution functions (IEDF, EEDF). These typically require knowledge of the first second derivatives I-V characteristics, both which can be obtained in various ways. This poses challenges inherent differentiating noisy signals, a frequent problem with electric-probe plasma diagnostics. A brief revie...

An experimental investigation of the operating characteristics of 3.2 mm diameter orificed hollow cathodes was conducted to examine low-current and low flow rate operation. Cathode power was minimized with low orifice aspect ratio and the use of an enclosed keeper. Cathode flow rate requirements were proportional to orifice diameter and the inverse of the orifice length. Cathode temperature pro...