Banca de DEFESA: BRUNO PIRES SIQUEIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : BRUNO PIRES SIQUEIRA
DATA : 06/03/2020
HORA: 14:00
LOCAL: Auditório, 8º andar, Bloco B, Campus SA da Fundação Universidade Federal do ABC, localizada na Avenida dos Estados, 5001, Santa Terezinha, Santo André, SP
TÍTULO:

Inertial effects on axisymmetric instabilities in cylindrical tokamaks

PÁGINAS: 107
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
SUBÁREA: Física dos Fluídos, Física de Plasmas e Descargas Elétricas
ESPECIALIDADE: Física de Plasmas e Descargas Elétricas
RESUMO:

In this work, we consider a generalization of Ohm's Law, taking the limits in which the electric field in the ideal plasma reference frame is proportional to the time rate of change of the current density; the proportion takes into account effects due to a finite electron mass. We show that those same limits are true when n_e, the electron number density, is suciently small. We also show that ν_ei, the electron-ion collision frequency, is much smaller than ω_ci, the ion cyclotron frequency. Combination of the later condition with Lawson criterion, for the deuterium-tritium fusion in ITER, gives us a lower bound for the geometric mean of τ_C, the confinement time, and the collision interval, (τ_C/ν_ei)^1/2 >> 10⁻⁵ s. In this context we estimate that n_e ∼ 10¹⁹ m⁻³ and compare typical parameters of our plasma with plasmas in others scenarios. When n_e has a low spatial and temporal variation, we generalize Alfvén's theorem, where the flux of an effective magnetic field is constant, which depends on a finite electron skin depth. As a consequence, we are able to define an effective safety factor, from which is possible to identify effective rational surfaces, shifted with respect to the standard ones. By considering helical perturbations on a cylindrical tokamak in an axisymmetric equilibrium, we are lead to the dispersion relation. That relation is then applied to the peaked model, which supposes a logarithmic derivative profile for the poloidal component of the equilibrium magnetic field. Our analytical formulation shows that inertial effects may triple the instability peak. In addition, the radius of the stable cylindrical column may increase by two orders of magnitude, when we include a finite electron mass.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 2604186 - FRANCISCO EUGENIO MENDONCA DA SILVEIRA
Membro Titular - Examinador(a) Interno ao Programa - 1907614 - MAURICIO RICHARTZ
Membro Titular - Examinador(a) Interno ao Programa - 1549709 - GERMAN LUGONES
Membro Titular - Examinador(a) Externo à Instituição - IBERÊ LUIZ CALDAS - USP
Membro Titular - Examinador(a) Externo à Instituição - RICARDO MAGNUS OSÓRIO GALVÃO - USP
Membro Suplente - Examinador(a) Interno ao Programa - 382324 - VILSON TONIN ZANCHIN
Membro Suplente - Examinador(a) Interno ao Programa - 2616823 - ALYSSON FABIO FERRARI
Membro Suplente - Examinador(a) Externo à Instituição - JOSÉ HELDER FACUNDO SEVERO - USP
Membro Suplente - Examinador(a) Externo à Instituição - ZWINGLIO DE OLIVEIRA GUIMARÃES FILHO - USP