LASER GENERATED PLASMAS OF VARIOUS ELEMENTS
UNDER MAGNETIC FIELD
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C. Ducruet, 1 C. de Julián Fernández, 1 N. Kornilov and 1 D. Givord
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Laboratoire Louis Néel and 2 CRETA, C.N.R.S.,
B.P. 166, 25 avenue des Martyrs, 38042 Grenoble Cedex 9, FRANCE
The properties of laser generated plasmas have been studied. In the considered experimental
conditions and for all studied elements (Al, Cu, Fe, Mo, Pt), the majority of the evaporated
species are ions, with typical energies in the range 60 eV - 100 eV. Due to excitation and
recombination mechanisms, the adiabatic constant which governs expansion (temperature,
angular distribution) is around 1.2, in agreement with literature, and less than the value 5/3
expected for a monoatomic gas. Langmuir probe measurements confirmed that plasma expansion
is inertial in zero magnetic field. From I-V characteristics, the electronic temperature was
extracted and found superior for volatile elements.
Strong plasma confinement was found to occur under a magnetic field, B, of up to 5 T. At 7 cm
from the target, 75 % of all evaporated material was deposited on a 35 mm diameter substrate
facing the target. The initial plasma temperature then deduced is of the order of 105 K. To first
order, the ion energy distribution is not affected by the field. The observed decrease of the
deposition rate as distance increases was attached to recombination effects. These are important
under magnetic field due to the huge plasma density, 1 to 2 orders of magnitude higher than in
zero field.
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TOPIC: Laser-matter interaction
PRESENTING: C. Ducruet
PREFERENCE: Talk
CORRESPONDENCE: Clarisse Ducruet
COMPLETE ADDRESS, EMAIL, TELEPHONE, AND FAX NUMBERS OF AUTHOR FOR
CORRESPONDENCE:
Clarisse Ducruet,
Laboratoire Louis Néel,
C.N.R.S.,
25 avenue des Martyrs,
B.P.166,
38042 Grenoble cedex 9,
FRANCE
Tel: +33 (0)4-76-88-10-90; Fax: +33 (0)4-76-88-11-91
EMAIL: ducruet@grenoble.cnrs.fr
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