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상세정보
spatio-temporal dynamics in systems driven far from equilibrium: lasers and fluids (waves). [microform]
spatio-temporal dynamics in systems driven far from equilibrium: lasers and fluids (waves). [microform]
상세정보
- 자료유형
- 마이크로피시
- 청구기호
- 저자명
- 서명/저자
- spatio-temporal dynamics in systems driven far from equilibrium: lasers and fluids (waves). - [microform]
- 발행사항
- 형태사항
- 204 p. : microfiches ; 11×15 cm.
- 총서명
- UMI Dissertation
- 주기사항
- Source: Dissertation Abstracts International, Volume: 57-10, Section: B, page: 6341.
- 학위논문주기
- thesis (ph.d.)-- - drexel university, 1996.
- 초록/해제
- 요약Two systems able to display spatio-temporal structures when driven far from equilibrium have been studied. The spatio-temporal structures appear when the systems undergo bifurcations and they are the manifestation of the symmetry breaking of some property. (a) A very simple fluid experiment shows the appearance of sources and sinks of traveling waves in a one dimensional setting. The emphasis has been in the interaction between sinks and sources. By measuring both the wavelength and frequency of the traveling waves as well as the velocity of sinks and sources it was possible to compare theory with experiment. In particular, the so-called kinematic formula for localized structures in a one dimensional system was verified for the first time to our knowledge. However, discrepancies between theory and experiment have also been found, thus suggesting that it is worth considering both additional measurements and the revision of some theoretical aspects. (b) A CO$\sb2$ laser experiment (main part of the thesis), in which a discharge tube with square cross section is used, displays two dimensional patterns in the plane perpendicular to the direction of propagation of the beam. We studied these patterns in three different ways: (i) Spatio-temporal structures in patterns of small to moderate Fresnel number were studied by means of bifurcation theory in the presence of a symmetry group. Two sequences of bifurcations were observed and afterwards identified by means of the Hopf Equivariant Theorem applied to the group D$\sb4$. (ii) Time-averaged spatial structures in patterns covering the whole range of available Fresnel numbers were analyzed using a Biorthogonal Decomposition. It was found that all the patterns, regardless of their size, can be described in terms of a small number of modes (less than five). (iii) Time series for the laser intensities at isolated points in patterns of big Fresnel number were analyzed. Global models were built by means of a Time Delay Embedding Algorithm. It was found that a five dimensional embedding space is able to support the dynamics.
- 복제주기
- Microfiche : UMI . microfiches;11×15 cm.
- 일반주제명
- 일반주제명
- 키워드
- 기타저자
- 기본자료저록
- Dissertation Abstracts International. 57-10B.
MARC
008970923s1996 us eng■001MOKWON00234154
■001AAV9707546
■00519990922143635
■008970923s1996 us eng
■035 ▼a(UnM)AAV9707546
■040 ▼aUnM▼cUnM▼dMOKWON
■090 ▼a530▼bA473s
■1001 ▼aalvarez, roberto fernando.
■24510▼aspatio-temporal dynamics in systems driven far from equilibrium: lasers and fluids (waves).▼h[microform]
■260 ▼aU.S.▼bdrexel university▼c1996.
■300 ▼a204 p.▼bmicrofiches▼c11×15 cm.
■350 ▼a$50.6
■44000▼aUMI Dissertation
■500 ▼aSource: Dissertation Abstracts International, Volume: 57-10, Section: B, page: 6341.
■502 ▼athesis (ph.d.)--▼bdrexel university▼d1996.
■520 ▼aTwo systems able to display spatio-temporal structures when driven far from equilibrium have been studied. The spatio-temporal structures appear when the systems undergo bifurcations and they are the manifestation of the symmetry breaking of some property. (a) A very simple fluid experiment shows the appearance of sources and sinks of traveling waves in a one dimensional setting. The emphasis has been in the interaction between sinks and sources. By measuring both the wavelength and frequency of the traveling waves as well as the velocity of sinks and sources it was possible to compare theory with experiment. In particular, the so-called kinematic formula for localized structures in a one dimensional system was verified for the first time to our knowledge. However, discrepancies between theory and experiment have also been found, thus suggesting that it is worth considering both additional measurements and the revision of some theoretical aspects. (b) A CO$\sb2$ laser experiment (main part of the thesis), in which a discharge tube with square cross section is used, displays two dimensional patterns in the plane perpendicular to the direction of propagation of the beam. We studied these patterns in three different ways: (i) Spatio-temporal structures in patterns of small to moderate Fresnel number were studied by means of bifurcation theory in the presence of a symmetry group. Two sequences of bifurcations were observed and afterwards identified by means of the Hopf Equivariant Theorem applied to the group D$\sb4$. (ii) Time-averaged spatial structures in patterns covering the whole range of available Fresnel numbers were analyzed using a Biorthogonal Decomposition. It was found that all the patterns, regardless of their size, can be described in terms of a small number of modes (less than five). (iii) Time series for the laser intensities at isolated points in patterns of big Fresnel number were analyzed. Global models were built by means of a Time Delay Embedding Algorithm. It was found that a five dimensional embedding space is able to support the dynamics.
■533 ▼aMicrofiche▼cUMI▼emicrofiches;11×15 cm.
■590 ▼aSchool code: 0065.
■650 4▼aPhysics, Optics
■650 4▼aPhysics, Fluid and Plasma
■653 ▼aspatio-temporal▼adynamics▼ain▼asystems▼adriven▼afar▼afrom▼aequilibrium▼alasers▼aand▼afluids▼a(waves).
■690 ▼a0752
■690 ▼a0759
■71020▼adrexel university.
■7730 ▼tDissertation Abstracts International▼g57-10B.
■790 ▼a0065
■791 ▼aPH.D.
■792 ▼a1996
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