Coexistence of turbulence regimes in the Texas Helimak

Autor(es)

Pereira, F. A. C. ^{[1, 2]} ; Toufen, D. L. ^[3] ; Guimaraes-Filho, Z. O. ^[2] ; Caldas, I. L. ^[2] ; Viana, R. L. ^[1] ; Gentle, K. W. ^{[4, 5]}

Afiliação do(s) autor(es)

^[1] Univ Fed Parana, Dept Phys, BR-81531990 Curitiba, Parana - Brazil

^[2] Univ Sao Paulo, Inst Phys, BR-05315970 Sao Paulo, SP - Brazil

^[3] Fed Inst Educ Sci & Technol Sao Paulo, BR-07115000 Guarulhos, SP - Brazil

^[4] Univ Texas Austin, Dept Phys, Austin, TX 78712 - USA

^[5] Univ Texas Austin, Inst Fus Studies, Austin, TX 78712 - USA

• Tipo de documento: Artigo Científico
• Fonte: Physics of Plasmas; v. 28, n. 3 MAR 2021.
• Citações Web of Science: 0

Resumo

The turbulence of magnetically confined plasmas usually presents high-density pulses with short duration known as bursts. In the Texas Helimak, it is possible to suppress bursts in a broader region by applying a negative electrostatic bias. However, an almost unchanged burst rate persists in a region far from the location where bias is applied. We investigate the turbulence transition that occurs from the burst suppressed region to the burst dominated region by analyzing data from Langmuir probes in the whole radial extension of the machine. We find that such turbulence transition can be understood as an alternation of two different turbulent regimes, with the probability of being in each regime depending on the radial position. One regime, named as burst-free regime, consists of only Gaussian fluctuations and the other, named as bursty turbulent regime, is a train of pulses with double exponential temporal profiles, exponential amplitude distribution, and random occurring instants. This succession between burst-free and bursty turbulent regimes influences the equilibrium parameters. (AU)

• Processo FAPESP: 18/03211-6 - Dinâmica não linear
• Beneficiário: Iberê Luiz Caldas
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 15/50122-0 - Fenômenos dinâmicos em redes complexas: fundamentos e aplicações
• Beneficiário: Elbert Einstein Nehrer Macau
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 17/23128-3 - Modelos para a turbulência e transporte no Texas Helimak
• Beneficiário: Felipe Augusto Cardoso Pereira
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado