TY - JOUR
T1 - Hierarchical instability of a vortex ring array in multipulse laser-matter interactions
AU - Lugomer, Stjepan
AU - Fukumoto, Yasuhide
N1 - Funding Information:
This paper is dedicated to the late Prof. R.B. Pelz. We are grateful to him for his interest and invaluable comments. In particular, it was he who turned our attention to the significance of baroclinic effect. He also kindly showed experimental results of S.L. to N.J. Zabusky. Y.F. was supported in part by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science.
PY - 2005/4
Y1 - 2005/4
N2 - In XeCl excimer Laser interactions with Co-coated steel surfaces, we have seemingly realized a quasi-linear array of vortex rings. These form from instabilities on an array of vortex filaments which emerge and then lead to a series of loops. Finally the collapse-and-reconnection process yields a cascade of nearby vortex rings. Since the filament array is subjected to randomly distributed local multipolar strains, unstable waves can develop on the vortex rings. These deformed shapes are frozen permanently by ultrafast cooling, following the last laser pulse. Using a modal analysis, an attempt is made to relate the wave structures to a parametric resonance instability which is caused by dipolar and a quadrupolar fields. Multipulse laser-matter interactions are thus capable of nonselective excitation of vortex ring instabilities of various sizes and various modal structures.
AB - In XeCl excimer Laser interactions with Co-coated steel surfaces, we have seemingly realized a quasi-linear array of vortex rings. These form from instabilities on an array of vortex filaments which emerge and then lead to a series of loops. Finally the collapse-and-reconnection process yields a cascade of nearby vortex rings. Since the filament array is subjected to randomly distributed local multipolar strains, unstable waves can develop on the vortex rings. These deformed shapes are frozen permanently by ultrafast cooling, following the last laser pulse. Using a modal analysis, an attempt is made to relate the wave structures to a parametric resonance instability which is caused by dipolar and a quadrupolar fields. Multipulse laser-matter interactions are thus capable of nonselective excitation of vortex ring instabilities of various sizes and various modal structures.
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U2 - 10.1016/j.fluiddyn.2004.06.005
DO - 10.1016/j.fluiddyn.2004.06.005
M3 - Article
AN - SCOPUS:15944409001
SN - 0169-5983
VL - 36
SP - 277
EP - 290
JO - Fluid Dynamics Research
JF - Fluid Dynamics Research
IS - 4-6
ER -