Plasma confinement in tokamaks with robust torus

We present a non-linear symplectic map that describes the alterations of the magnetic field lines inside the tokamak plasma due to the presence of a robust torus (RT) at the plasma edge. This RT prevents the magnetic field lines from reaching the tokamak wall and reduces, in its vicinity, the islands and invariant curve destruction due to resonant perturbations. The map describes the equilibrium magnetic field lines perturbed by resonances created by ergodic magnetic limiters (EMLs). We present the results obtained for twist and non-twist mappings derived for monotonic and non-monotonic plasma current density radial profiles, respectively. Our results indicate that the RT implementation would decrease the field line transport at the tokamak plasma edge. © 2010 Elsevier B.V. All rights reserved.

Zoneamento do parque ecológico de ourinhos SP

The aim of this study was to carry out a zoning in the municipal ecological park of Ourinhos, SP, located southwest of São Paulo State, aiming to subsidize the planning and management of this area. With this purpose it was made an inventory of the landscape resources of this park with hypsometry, declivity, use of soil and zoning mappings. From this zoning, we analyzed the possibilities of implementing purposes of use, with the objective of preserving this area, minimizing the negative environmental impacts. Thus, this research was of extreme importance, since it allowed to identify and rank, in the territory, areas or sectors that are priority to the development of activities, as well as contribute to the conservation of natural and socio-cultural heritage.

Geometrical wave equation and the cauchy-like theorem for octonions

Riemann surfaces, cohomology and homology groups, Cartan's spinors and triality, octonionic projective geometry, are all well supported by Complex Structures [1], [2], [3], [4]. Furthermore, in Theoretical Physics, mainly in General Relativity, Supersymmetry and Particle Physics, Complex Theory Plays a Key Role [5], [6], [7], [8]. In this context it is expected that generalizations of concepts and main results from the Classical Complex Theory, like conformal and quasiconformal mappings [9], [10] in both quaternionic and octonionic algebra, may be useful for other fields of research, as for graphical computing enviromment [11]. In this Note, following recent works by the autors [12], [13], the Cauchy Theorem will be extended for Octonions in an analogous way that it has recentely been made for quaternions [14]. Finally, will be given an octonionic treatment of the wave equation, which means a wave produced by a hyper-string with initial conditions similar to the one-dimensional case.

One-dimensional Fermi accelerator model with moving wall described by a nonlinear van der Pol oscillator

A modification of the one-dimensional Fermi accelerator model is considered in this work. The dynamics of a classical particle of mass m, confined to bounce elastically between two rigid walls where one is described by a nonlinear van der Pol type oscillator while the other one is fixed, working as a reinjection mechanism of the particle for a next collision, is carefully made by the use of a two-dimensional nonlinear mapping. Two cases are considered: (i) the situation where the particle has mass negligible as compared to the mass of the moving wall and does not affect the motion of it; and (ii) the case where collisions of the particle do affect the movement of the moving wall. For case (i) the phase space is of mixed type leading us to observe a scaling of the average velocity as a function of the parameter (χ) controlling the nonlinearity of the moving wall. For large χ, a diffusion on the velocity is observed leading to the conclusion that Fermi acceleration is taking place. On the other hand, for case (ii), the motion of the moving wall is affected by collisions with the particle. However, due to the properties of the van der Pol oscillator, the moving wall relaxes again to a limit cycle. Such kind of motion absorbs part of the energy of the particle leading to a suppression of the unlimited energy gain as observed in case (i). The phase space shows a set of attractors of different periods whose basin of attraction has a complicated organization. © 2013 American Physical Society.

Saddle points and rare collisions under scaling approach in a Fermi accelerator with two nonlinear terms

Rare collisions of a classical particle bouncing between two walls are studied. The dynamics is described by a two-dimensional, nonlinear and area-preserving mapping in the variables velocity and time at the instant that the particle collides with the moving wall. The phase space is of mixed type preventing diffusion of the particle to high energy. Successive and therefore rare collisions are shown to have a histogram of frequency which is scaling invariant with respect to the control parameters. The saddle fixed points are studied and shown to be scaling invariant with respect to the control parameters too. © 2012 Elsevier B.V. All rights reserved.

Controle aproximado para sistemas não-lineares de equações diferenciais ordinárias

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sistema hierárquico de classificação para mapeamento da cobertura da terra nas escalas regional e urbana

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estruturas shrimp e propriedades dinâmicas no modelo dissipativo do acelerador de Fermi

Pós-graduação em Física - IGCE

Transições de fase nas dinâmicas de uma partícula se movendo em um poço ou barreira de potencial dependentes periodicamente do tempo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Zoneamento geoambiental do município de São João da Boa Vista (SP)

Pós-graduação em Geociências e Meio Ambiente - IGCE

Sedenions Cayley-dickson e dilatação de funções k-quaseconformes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Analiticidade e efeito gráfico da dilatação em funções octoniônicos quaseconformes do tipo F(Z)=Zn

Pós-graduação em Matemática - IBILCE

Uma abordagem para classificação de funções k-quaseconformes

Pós-graduação em Matemática - IBILCE

A cartografia na era da cibercultura: mapeando outras geografias no ciberespaço

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A dinâmica do uso da terra e sua interferência na morfohidrografia da Bacia do Arroio Santa Bárbara - Pelotas (RS)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)