Abstract: | Pulsed plasma thrusters (PPTs) are an attractive form of micro-thrusters due to advantages such
as their compactness and lightweight design compared to other electric propulsion systems.
Experimental investigations on their plasma properties are beneficial in clarifying the complex
process of plasma evolution during the micro-second pulse discharge of a PPT. In this work, the
multi-dimensional evolutions of the light intensity of the PPT plasma with wavelength, time, and
position were identified. The plasma pressure was obtained using an iterative process with
composition calculations. The results show that significant ion recombination occurred in the
discharge channel since the line intensities of CII, CIII, CIV, and FII decreased and those of CI
and FI increased as the plasma moved downstream. At the center of the discharge channel, the
electron temperature and electron density were in the order of 10000 K and 10 17 cm ?3,
respectively. These had maximum values of 13 750 K and 2.3×10 17 cm ?3 and the maximum
temperature occurred during the first half-cycle while the maximum number density was
measured during the second half-cycle. The estimated plasma pressure was in the order of 10 5 Pa
and exhibited a maximum value of 2.69×10 5 Pa. |