1995 Fiscal Year Final Research Report Summary
Defect patterns and bifurcation in the electroconvection
| Project/Area Number |
06452066
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
物性一般(含基礎論)
|
|---|
| Research Institution | KYUSHU UNIVERSITY |
|---|
Principal Investigator |
S Kai Kyushu Univ., Appl.Phys., Prof., 工学部, 教授 (20112295)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
S Nasuno Kyushu Inst.Tech., Elect.Engin., Lecturer, 工学部, 講師 (90228073)
|
|---|
| Project Period (FY) |
1994 – 1995
|
| Keywords | Liquid Crystal / Electrohydrodynamic Convection / Homeotropic / Scaling / Phase Slip / Defect / Topological Dynamics / Busse Diagram |
|---|
| Research Abstract |
Weakly nonlinear evolutions and secondary instabilities near convective onset in the electrohydrodynamic instability (EHC) in liquid crystals which is one of most convenient and suitable research objects have been investigated as well as their bifurcation mechanisms and dynamics. We obtain the following results. (1) There are three characteristic dynamics in one dimensional pattern selection processes, such as simple elastic relaxation, stable and Eckhaus unstable states which are also experimentally defined. In Eckhaus instability, growth rate and the fastest growing unstable mode was quantitatively measured and their dependences on the difference from the critical mode were experimentally determined which were in good agreement with theoretical predictions. (2) The universal spatio-temporal scaling law was found in phaseslip (PS) processes in a one-dimensional system. In the macroscopic scaling in the Ginzburg-Landau phase the scaling coefficient was exactly determined experimentally
… More
and theoretically. (3) In a two-dimensional system, three toporogically different PS (defect creation/annihilation) processes were observed. They showed the same scaling law as in a one-dimensional system. In addition, the universal scaling appears to hold only near PS points and homever far from PS point the dynamics is dominated by the phase diffusion process not by PS dynamics. (4) In the hometropic EHC which has an additional symmetry such as the Goldstone mode, pattern formation process was complicated and no Busse diagram was observed. The soft turbulence was observed at theconvective onset by the supercritical bifurcation. It has been the first experimental observation to occur a chaos through such a bifurcation root. The Busse diagram, however, was observed when the magnetic field was applied to the system which can kill the Goldstone mode and change the symmetry. In this condition, it was also found that the Busse diagram was quite different from the conventional Busse diaram observed in the Rayleigh-Benard convection and the planer EHC. Less
|
