Nonequilibrium energy transport taking place in the surface region of the metallic substrate due to laser short-pulse heating results in entropy production in electron and lattice systems. The entropy analysis gives insight into the irreversible processes taking place in this region during the laser short-pulse heating process. In the present study, entropy production during laser shortpulse heating of copper is considered. Equations governing the nonequilibrium energy transport are derived using an electron kinetic theory approach. The entropy equations due to electron and lattice systems and coupling of these systems are formulated. The governing equations of energy transport and entropy production are solved numerically. Two pulse shapes, namely step input intensity and exponential intensity, are employed in the analysis. It is found that entropy production due to coupling process attains higher values than those produced due to electron and lattice systems. The effect of pulse shape on the entropy production inside the substrate material is significant.

Issue Section:
Technical Papers
Keywords:
laser ablation, copper, entropy, nonequilibrium thermodynamics, heat transfer
Topics:
Copper, Electrons, Entropy, Heating, Lasers, Temperature, Shapes
1.
Fujimoto
,
J. G.
,
Liu
,
J. M.
, and
Ippen
,
E. P.
,
1984
, “
Femtosecond Laser Interaction With Metallic Tungsten and Nonequilibrium Electron and Lattice Temperatures
,”
Phys. Rev. Lett.
,
53
, pp.
1837
–
1840
.
2.
Elsayed-Ali
,
H. E.
,
Norris
,
T. B.
,
Pessot
,
M. A.
, and
Mourou
,
G. A.
,
1987
, “
Time-Resolved Observation of Electron-Phonon Relaxation in Copper
,”
Phys. Rev. Lett.
,
58
, No.
12
, pp
1212
–
1215
.
3.
Eesley
,
G. L.
,
1986
, “
Generation of Nonequilibrium Electron and Lattice Temperatures in Copper by Picosecond Laser Pulses
,”
Phys. Rev. B
,
33
, pp.
2144
–
2151
.
4.
Qiu
,
T. Q.
, and
Tien
,
C. L.
,
1994
, “
Femtosecond Laser Heating of Multi-Layer Metals—I. Analysis
,”
Int. J. Heat Mass Transf.
,
37
, No.
17
, pp
2789
–
2797
.
5.
Wang
,
X. Y.
,
Riffe
,
D. M.
,
Lee
,
Y. S.
, and
Downer
,
M. C.
,
1994
, “
Time-Resolved Electron-Temperature Measurement in a Highly Excited Gold Target Using Femtosecond Thermionic Emission
,”
Phys. Rev. B
,
50
, pp.
8016
–
8019
.
6.
Tzou
,
D. Y.
,
1995
, “
A Unified Field Approach for Heat Conduction From Macro-to-Micro-Scales
,”
ASME J. Heat Transfer
,
117
, pp.
8
–
16
.
7.
Al-Nimr
,
M. A.
, and
Arpaci
,
V. S.
,
1999
, “
Picosecond Thermal Pulses in Thin Metal Films
,”
J. Appl. Phys.
,
85
, pp.
2517
–
2521
.
8.
Yilbas
,
B. S.
,
1986
, “
Heating of Metals at a Free Surface by Laser Radiation an Electron Kinetic Theory Approach
,”
Int. J. Eng. Sci.
,
24
, No.
8
, pp.
1325
–
1334
.
9.
Yilbas
,
B. S.
, and
Shuja
,
S. Z.
,
1999
, “
Laser Short-Pulse Heating of Surfaces
,”
J. Phys. D
,
32
, pp.
1947
–
1954
.
10.
Sieniutycz
,
S.
,
1999
, “
Carnot Problem of Maximum Work From a Finite Resource Interacting With Environment in a Finite Time
,”
Physica A
,
264
, pp.
234
–
263
.
11.
Menshutina
,
N. V.
, and
Darokhov
,
I. N.
,
1996
, “
Simulation of Drying on the Basis of Nonequilibrium Thermodynamics of Heterogeneous Multiphase Polydispersed Systems
,”
Drying Technol.
,
14
, pp.
915
–
921
.
12.
Demirel
,
Y.
, and
Sandler
,
S. I.
,
2001
, “
Linear-Nonequilibrium Thermodynamics Theory for Coupled Heat and Mass Transport
,”
Int. J. Heat Mass Transf.
,
44
, pp.
2439
–
2451
.
13.
Yilbas
,
B. S.
,
1999
, “
Three-Dimensional Laser Heating Model and Entropy Generation Consideration
,”
ASME J. Energy Resour. Technol.
,
121
, pp.
217
–
224
.
14.
Yilbas
,
B. S.
, and
Sahin
,
A. Z.
,
1993
, “
An Approach to Convergency of Kinetic Theory to Fourier Theory in Relation to Laser Heating Process
,”
Jpn. J. Appl. Phys.
,
32
, Part 1, No.
12A
, pp.
5646
–
5651
.
15.
Corkum
,
P. B.
,
Brunel
,
F.
, and
Sherman
,
N. K.
,
1988
, “
Thermal Response of Metals to Ultrashort-pulse Laser Excitations
,”
Phys. Rev. Lett.
,
25
, pp.
2886
–
2889
.
16.
Sonntag R. E., and Van Wylen G. J., 1976, Fundamentals of Statistical Thermodynamics, “Series in Thermal and Transport Sciences, 1st Edited, John Wiley and Sons Inc., New York, NY.
17.
Smith G. D., 1985, Numerical Solution of Partial Differential Equations: Finite Difference Methods, 3rd Edition Clarendon Press, Oxford, UK.
Copyright © 2002
 by ASME
You do not currently have access to this content.