Mapping neutral, ion and electron number densities within laser ablated plasma plumes

I. Weaver, L.A. Doyle, G.W. Martin, David Riley, Martin Lamb, Bill Graham, Thomas Morrow, Ciaran Lewis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

Spatially and temporally varying neutral, ion and electron number densities have been mapped out within laser ablated plasma plumes expanding into vacuum. Ablation of a magnesium target was performed using a KrF laser, 30 ns pulse duration and 248 nm wavelength. During the initial stage of plasma expansion (t <EQ 100 ns) interferometry has been used to obtain line averaged electron number densities, for laser power densities on target in the range 1.3 - 3.0 X 108 W/cm2. Later in the plasma expansion (t equals 1 microsecond(s) ) simultaneous absorption and laser induced fluorescence spectroscopy has been used to determine 3D neutral and ion number densities, for a power density equal to 6.7 X 107 W/cm2. Two distinct regions within the plume were identified. One is a fast component (approximately 106 cm-1) consisting of ions and neutrals with maximum number densities observed to be approximately 30 and 4 X 1012 cm-3 respectively, and the second consists of slow moving neutral material at a number density of up to 1015 cm-3. Additionally a Langmuir probe has been used to obtain ion and electron number densities at very late times in the plasma expansion (1 microsecond(s) <EQ t <EQ 15 microsecond(s) ). A copper target was ablated using a Nd:YAG laser, 7.5 ns duration and 532 nm (2 (omega) ) wavelength, with a power density on target equal to 6 X 108 W/cm2. Two regions within the plume with different velocities were observed. Within a fast component (approximately 3 X 106 cms-1) electron and ion number densities of the order 5 X 1012 cm-3 were observed and within the second slower component (approximately 106 cms-1) electron and ion number densities of the order 1 - 2 X 1013 cm-3 were determined.
Original languageEnglish
Title of host publicationProceedings SPIE 3404: ALT'97 International Conference on Laser Surface Processing
Pages341-350
Number of pages10
Volume3404
DOIs
Publication statusPublished - Sep 1998
EventALT 97 International Conference on Laser Surface Processing - Limoges, France
Duration: 01 Sep 199801 Sep 1998

Conference

ConferenceALT 97 International Conference on Laser Surface Processing
CountryFrance
CityLimoges
Period01/09/199801/09/1998

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  • Cite this

    Weaver, I., Doyle, L. A., Martin, G. W., Riley, D., Lamb, M., Graham, B., Morrow, T., & Lewis, C. (1998). Mapping neutral, ion and electron number densities within laser ablated plasma plumes. In Proceedings SPIE 3404: ALT'97 International Conference on Laser Surface Processing (Vol. 3404, pp. 341-350) https://doi.org/10.1117/12.308637