Volume 95, Issue 5, 01 March 2004
Index of content:
- PLASMAS AND ELECTRICAL DISCHARGES (PACS 51-52)
95(2004); http://dx.doi.org/10.1063/1.1644043View Description Hide Description
A two-dimensional self-consistent simulation of a miniaturized inductively coupled plasma (mICP) reactor was developed. The coupled equations for plasma power deposition, electron temperature, and charged and neutral species densities, were solved to obtain the spatial distribution of an argon discharge. The effect of control parameters, such as power and pressure, on the evolution of plasma density and electron temperature was investigated. Strong ion density gradients were observed which can make spatially resolved Langmuir probe measurements particularly challenging. Simulation results were in reasonable agreement with available experimental data. The neutral gas temperature was predicted to be close to the wall temperature, due to the small length scale of the mICP, allowing for efficient heat transfer.
95(2004); http://dx.doi.org/10.1063/1.1645670View Description Hide Description
The energy distribution of electrons ejected from laser-induced plasma was measured using a magnetic spectrometer. The spectrometer was developed for quantitative analysis using an imaging plate. The efficiency of the imaging plate for detecting energetic electrons was calibrated using a transmission electron microscope, which accelerates electrons into energies between 80 and 200 keV. The kinetic energy distribution of electrons, which are ejected towards the backward direction, was measured on a copper bulk target irradiated with an infrared 60 fs laser. The obtained effective electron temperature in the energy range between 60 and 200 keV corresponded to approximately 130 keV at an intensity of This temperature was consistent with a scaling of by Beg et al. [Phys. Plasma 4, 447 (1997)] derived from resonance absorption.
95(2004); http://dx.doi.org/10.1063/1.1642734View Description Hide Description
Conventional annular Hall thrusters become inefficient when scaled to low power. Their lifetime decreases significantly due to the channel wall erosion. Cylindrical Hall thrusters, which have lower surface-to-volume ratio and, thus, seem to be more promising for scaling down, exhibit performance comparable with conventional annular Hall thrusters of the similar size. Plasma potential, ion density, and electron temperature profiles were measured inside the 2.6 cm cylindrical Hall thruster with the use of stationary and slow movable emissive and biased Langmuir probes. Potential drop in the 2.6 cm cylindrical Hall thruster is localized mainly in the cylindrical part of the channel and in the plume, which suggests that the thruster should suffer lower erosion of the channel walls due to fast ion bombardment. Plasma density has a maximum of about at the thruster axis. At the discharge voltage of 300 V, the maximum electron temperature is about 21 eV, which is not enough to produce multiple ionization in the accelerated flux of ions.