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Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers
Published on: October 17, 2013
Effective transport barriers in nontwist systems
J D Szezech1, I L Caldas, S R Lopes
1Instituto de Física, Universidade de São Paulo, 5315-970, São Paulo, São Paulo, Brazil.
Summary
Transport barriers emerge in shearless regions of fluids and plasmas, linked to chaos transition. This study reveals how stickiness structures in nontwist maps create effective barriers, crucial for understanding plasma transport.
Area of Science:
- Nonlinear dynamics
- Plasma physics
- Fluid dynamics
Background:
- Zonal flows in fluids and plasmas can exhibit reversed shear.
- Transport barriers are crucial for understanding particle and energy transport.
- Nontwist maps model complex dynamics in such systems.
Purpose of the Study:
- To investigate the formation and characteristics of transport barriers in shearless regions.
- To analyze the parameter dependence of transport through broken shearless barriers.
- To understand the role of stickiness and homoclinic tangles in barrier formation.
Main Methods:
- Utilizing the standard nontwist map to model zonal flows.
- Varying a control parameter to observe changes in transport.
- Analyzing stickiness structures and their relation to homoclinic tangles.
- Employing the finite-time rotation number as a diagnostic tool.
Main Results:
- Identified onset of structures with high stickiness near broken shearless curves.
- Demonstrated that stickiness structures create effective transport barriers.
- Showed that homoclinic tangles of twin island chains determine these stickiness structures.
- Validated the finite-time rotation number for identifying transport barriers.
Conclusions:
- Stickiness structures associated with homoclinic tangles effectively reduce transport in shearless regions.
- The finite-time rotation number is a reliable diagnostic for identifying transport barriers.
- These findings provide insights into chaos transition routes and transport phenomena in plasmas and fluids.
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